A crystalline CMOF catalyst for removing water pollutants by contact electrocatalysis and a preparation method and application thereof

Abstract

The application discloses a crystalline CMOF catalyst for removing water pollutants through contact electrocatalysis and a preparation method and application thereof, wherein the preparation method of the crystalline CMOF catalyst comprises the following steps: S1, uniformly mixing a metal salt, an organic ligand, an adjusting agent and a solvent to form a mixed solution, and performing a crystallization reaction to generate crystalline metal organic framework particles (crystalline CMOF particles); and S2, purifying the crystalline metal organic framework particles, and then performing vacuum activation to open pores of the crystalline metal organic framework particles, so as to obtain a crystalline metal organic framework catalyst (crystalline CMOF catalyst).

Description

Technical Field

[0001] This application belongs to the technical field of contact electrocatalysis, specifically, a crystalline CMOF catalyst for the removal of water pollutants by contact electrocatalysis, its preparation method, and its application. Background Technology

[0002] Currently, the main technologies for removing organic pollutants in water (such as sulfadiazine and bisphenol A) include photocatalysis, electrochemical oxidation, and traditional advanced oxidation processes (AOPs). These methods generally rely on external energy input or the addition of chemical oxidants to maintain the reaction process, resulting in high energy consumption and complex systems. Contact electrocatalysis (CEC) technology, on the other hand, relies on charge transfer between materials to drive chemical reactions. During contact electrification, the contact between materials causes a redistribution of electrons, generating a potential difference. This potential difference effectively activates reactant molecules, thereby lowering the energy barrier of the chemical reaction and promoting its occurrence. CEC technology can achieve highly efficient catalysis under various environmental conditions, demonstrating enormous application potential.

[0003] CEC technology is used to remove pollutants from water. It typically consists of a friction layer / contact electrode, a conductive substrate, and a conventional catalytic layer (such as TiO2, ZnO, FCP, etc.). It generates a potential difference through contact-separation, sliding friction, or water flow impact, driving electron migration at the electrode-solution interface and generating hydroxyl radicals. · OH), superoxide anion radical (O2) ·- The method generally involves: constructing contact electrification units → periodic contact electrification → generation of active species at the interface → degradation of organic pollutants.

[0004] However, conventional catalytic materials currently used in contact electrocatalytic removal of water pollutants have shortcomings such as low utilization of the interfacial electric field and insufficient activation of catalytic active sites, and their degradation effect on organic pollutants needs to be improved.

[0005] In view of this, this application provides a crystalline CMOF catalyst for contact electrocatalytic removal of water pollutants, its preparation method, and its application. When applied to contact electrocatalytic removal of water pollutants, the CMOF catalyst improves electron migration efficiency, active oxygen group generation efficiency, and pollutant enrichment capacity, thereby achieving efficient removal of organic pollutants in water under low energy consumption conditions. Furthermore, the CMOF catalyst has good structural stability and can be reused multiple times. Summary of the Invention

[0006] The purpose of this application is to provide a crystalline CMOF catalyst for contact electrocatalytic removal of water pollutants, its preparation method, and its application. When applied to contact electrocatalytic removal of water pollutants, the CMOF catalyst improves electron migration efficiency, active oxygen group generation efficiency, and pollutant enrichment capacity, thereby achieving efficient removal of organic pollutants in water under low energy consumption conditions. Furthermore, the CMOF catalyst has good structural stability and can be reused multiple times.

[0007] A first aspect of this application provides a method for preparing a crystalline CMOF catalyst for the electrocatalytic removal of water pollutants, comprising the steps of: S1, metal salt, organic ligand, regulator and solvent are mixed evenly to form a mixture, and crystallization reaction is carried out to generate crystalline metal-organic framework particles (crystalline CMOF particles). S2, purify the crystalline metal-organic framework particles, then activate them under vacuum to open the pores of the crystalline metal-organic framework particles, and obtain a crystalline metal-organic framework catalyst (crystalline CMOF catalyst).

[0008] In some embodiments, the metal salt includes at least one of iron salt, copper salt, cobalt salt, nickel salt, zirconium salt, or titanium salt.

[0009] In some embodiments, the organic ligand is an acidic organic ligand.

[0010] Furthermore, the acidic organic ligand includes at least one of the following: terephthalic acid, aminoterephthalic acid, pyromellitic acid, nitrogen-containing multidentate acidic organic ligand, isophthalic acid, or phthalic acid.

[0011] In some embodiments, the regulator is used to control the nucleation and growth rate of CMOF crystals.

[0012] Furthermore, the regulator includes at least one of glacial acetic acid, acetic acid, formic acid, lauric acid, or sodium formate.

[0013] In some embodiments, the solvent is a polar solvent with a dielectric constant ≥30 at 25°C.

[0014] In some embodiments, the concentration of the organic ligand in the mixture is 1-2 wt%, and the mass ratio of the organic ligand, the metal salt, and the regulator is 1:(1-2.2):(5-7.5). Preferably, the concentration of the organic ligand in the mixture is 1.2-1.7 wt%, and the mass ratio of the organic ligand, the metal salt, and the regulator is 1:(1.4-1.9):(5.8-7).

[0015] In some embodiments, the mixture is heated to 100-140°C and subjected to a crystallization reaction for 15-20 hours to generate crystalline metal-organic framework particles (crystalline CMOF particles).

[0016] In some embodiments, in step S2, the purified crystalline metal-organic framework particles are activated under vacuum at 90-110°C for 8-12 hours to obtain a powdered crystalline CMOF catalyst.

[0017] In some embodiments, the step of purifying crystalline CMOF particles is as follows: centrifuge the solution containing crystalline CMOF particles in S1, collect the precipitate, wash it sequentially with the solvent and alcohol solvent, and then replace it in the alcohol solvent for 10-14 hours to obtain purified crystalline CMOF particles.

[0018] A second aspect of this application provides a crystalline CMOF catalyst for the contact electrocatalytic removal of water pollutants, wherein the crystalline CMOF catalyst is obtained by the above-described preparation method.

[0019] In some embodiments, the particle size of the crystalline CMOF catalyst is 50 nm to 5 μm.

[0020] In some embodiments, the pore size of the crystalline CMOF catalyst is 0.5-10 nm.

[0021] A third aspect of this application discloses a method for using crystalline CMOF catalysts in contact electrocatalytic removal of water pollutants, comprising the following steps: A1, the above-mentioned crystalline CMOF catalyst is mixed with an aqueous solution containing organic pollutants to form a solid-liquid reaction system; or the above-mentioned crystalline CMOF catalyst is fixed on a conductive substrate as a catalyst layer; A2, applying a force to the solid-liquid reaction system or the catalyst layer to trigger a contact electrocatalytic process, generating reactive oxygen groups, and the organic pollutants are degraded under the action of the reactive oxygen groups.

[0022] In some embodiments, in step A1, the concentration of the crystalline CMOF catalyst in the solid-liquid reaction system is 200-300 mg / L.

[0023] In some embodiments, in step A2, the applied force includes at least one of: ultrasound, mechanical vibration, liquid flow impact, stirring shear, or gas-liquid disturbance.

[0024] Furthermore, the ultrasonic treatment power is 80-150W, the frequency is 20-80kHz, and the temperature of the solid-liquid reaction system during ultrasonic treatment is 23-27℃.

[0025] Furthermore, the active oxygen group includes: hydroxyl radical ( · OH), or superoxide anion radical (O2) ·- At least one of the following.

[0026] Furthermore, the organic pollutants include at least one of the following: ibuprofen (IBU), norfloxacin (NOR), bisphenol A (BPA), sulfadiazine (SDZ), ornidazole, azo dyes, rhodamine B, or methyl orange.

[0027] In some embodiments, after the degradation reaction is completed, solid-liquid separation is achieved by sedimentation, filtration or centrifugation to recover the crystalline CMOF catalyst; after washing and drying, it can be reused for the next degradation of water pollutants to achieve multiple cycles of treatment, wherein the multiple cycles are ≤6 times.

[0028] The crystalline CMOF catalyst for the removal of water pollutants by contact electrocatalysis, its preparation method, and its application disclosed in this application have at least the following advantages compared with existing technologies: Firstly, this application uses crystalline CMOF as a catalyst in contact electrocatalysis technology. The intrinsically CMOF framework and the crystalline, ordered distribution of metal nodes serve as catalytic active centers, coupled with the periodic interfacial potential difference generated by contact electrification. Without requiring external electrical energy input, the interfacial potential difference generated by contact electrification excites the catalytic activity of the ordered metal nodes in the crystalline CMOF structure, enhancing electron migration efficiency and interfacial reactions, and increasing the activity of reactive oxygen species (hydroxyl radicals). · OH), superoxide anion radical (O2) ·- The formation rate of pollutants such as [list of pollutants] is reduced, thereby achieving low-energy and high-efficiency removal of pollutants in water. Furthermore, the crystalline CMOF catalyst of this application has a stable structure and can be reused multiple times.

[0029] Secondly, compared with ordinary MOF adsorption systems, the crystalline CMOF in this application, as a catalyst for contact electrocatalysis, enhances the interfacial potential drive through the contact electrocatalysis process. Relying on the ordered metal nodes and regular pore structure of the CMOF, organic pollutants are enriched at the pores and interfaces of the crystalline CMOF, providing mass transfer channels. Charge transfer and in-situ generation of reactive oxygen species occur near the metal nodes of the crystalline CMOF, improving electron migration efficiency, reactive oxygen species generation efficiency, and pollutant enrichment capacity, thereby achieving efficient removal of organic pollutants under low energy consumption conditions. Furthermore, this application does not involve post-metallization / secondary introduction of metal sites; the catalytic active center originates from the crystalline CMOF structure itself.

[0030] Thirdly, the crystalline CMOF catalyst of this application is applied to the removal of water pollutants by contact electrocatalysis. Through experimental verification, after 60 minutes of sonication, the degradation rate of ibuprofen (IBU), norfloxacin (NOR), and bisphenol A (BPA) can reach 100%. After the crystalline CMOF catalyst is recycled 6 times, there is no significant change in the removal efficiency of these three organic pollutants. The crystalline CMOF catalyst has excellent stability and can be reused multiple times. Attached Figure Description

[0031] Combined with the following appendix Figure 1 The above and other features of this application will be more fully described when the drawings are read. It is understood that these drawings only depict a few embodiments of the application and should not be considered as limiting the scope of the application. The application will be explained more clearly and in more detail through the use of the drawings.

[0032] Figure 1 This is a diagram showing the degradation effect of the crystalline CMOF catalyst on IBU in Example 3.

[0033] Figure 2 The graph shows the degradation effect of IBU on the crystalline CMOF catalyst after it was reused 6 times in Examples 3 and 4.

[0034] Figure 3 The image shows the degradation effect of the crystalline CMOF catalyst on NOR in Example 5.

[0035] Figure 4 The graph shows the degradation effect of NOR after the crystalline CMOF catalyst was reused 6 times in Examples 5 and 6.

[0036] Figure 5 The image shows the degradation effect of the crystalline CMOF catalyst on BPA in Example 7.

[0037] Figure 6 The graph shows the degradation effect of BPA on the crystalline CMOF catalyst after it was reused 6 times in Examples 7 and 8.

[0038] Figure 7 The graph shows the degradation effect of PVDF on IBU in Comparative Example 1.

[0039] Figure 8 The graph shows the degradation effect of PVDF on IBU after being used 6 times in Comparative Examples 1 and 2. Detailed Implementation

[0040] The following embodiments are described to aid in understanding this application. These embodiments are not, and should not be construed as, limiting the scope of protection of this application.

[0041] Unless otherwise defined, all terms (including technical and scientific terms) in this specification may be defined as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having meanings consistent with their meanings in the context of this disclosure and the relevant field, and will be interpreted in a non-idealized or overly formal sense unless clearly defined herein.

[0042] As used herein, the term "at least one," when modifying the entire list of elements without modifying any individual elements of the list before or after it, shall not be construed as limiting "one." The terms "comprising" and "including," when used in this specification, indicate the presence of the stated features, regions, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components, and / or collections thereof. Therefore, the above wording shall be understood to mean including the stated elements, but not excluding any other elements. The term "and / or" includes any and all combinations of one or more of the associated listed items. The term "multiple" refers to two or more. The term "connected" refers to a direct or indirect connection. The terms "first," "second," "third," etc., may be used herein to describe and distinguish different elements, components, regions, layers, and / or portions, but these elements, components, regions, layers, and / or portions should not be limited by these terms.

[0043] A first aspect of this application provides a method for preparing a crystalline CMOF catalyst for the electrocatalytic removal of water pollutants, comprising the steps of: S1, metal salt, organic ligand, regulator and solvent are mixed evenly to form a mixture, and crystallization reaction is carried out to generate crystalline metal-organic framework particles (crystalline CMOF particles). S2, purify the crystalline metal-organic framework particles, then activate them under vacuum to open the pores of the crystalline metal-organic framework particles, and obtain a crystalline metal-organic framework catalyst (crystalline CMOF catalyst).

[0044] This application utilizes crystalline CMOF as a catalyst in contact electrocatalysis technology. The intrinsically CMOF framework and the ordered, crystalline metal nodes serve as catalytic active centers, coupled with the periodic interfacial potential difference generated by contact electrification. Without requiring external electrical input, the interfacial potential difference generated by contact electrification excites the ordered metal nodes in the crystalline CMOF structure, enhancing electron migration efficiency and interfacial reactions, and increasing the activity of reactive oxygen species (hydroxyl radicals). · OH), superoxide anion radical (O2) ·-The formation rate of pollutants such as [list of pollutants] is reduced, thereby achieving low-energy and high-efficiency removal of pollutants in water. Furthermore, the crystalline CMOF catalyst of this application has a stable structure and can be reused multiple times.

[0045] In some embodiments, the metal salt includes at least one of iron salt, copper salt, cobalt salt, nickel salt, zirconium salt, or titanium salt.

[0046] The iron salts include at least one of ferric chloride, ferric chloride hexahydrate, ferric sulfate, ferric nitrate, or ferric phosphate. The copper salts include at least one of copper nitrate, copper nitrate trihydrate, copper acetate, copper citrate, or copper acetylacetonate. The cobalt salts include at least one of cobalt sulfate, cobalt chloride, cobalt nitrate, or cobalt acetate. The nickel salts include at least one of nickel sulfate, nickel chloride, nickel nitrate, or nickel acetate. The zirconium salts include at least one of zirconium sulfate or zirconium oxychloride. The titanium salts include at least one of titanium halide, titanate, titanium oxysulfate, or titanium trichloride. In addition to the listed iron, copper, cobalt, nickel, zirconium, and titanium salts, other common iron, copper, cobalt, nickel, zirconium, and titanium salts are also within the scope of protection of this application.

[0047] In some embodiments, the organic ligand is an acidic organic ligand.

[0048] Furthermore, the acidic organic ligand includes at least one of the following: terephthalic acid, aminoterephthalic acid, pyromellitic acid, nitrogen-containing multidentate acidic organic ligand, isophthalic acid, or phthalic acid. In addition to these listed acidic organic ligands, other common acidic organic ligands are also within the scope of protection of this application.

[0049] In some embodiments, the regulator is used to control the nucleation and growth rate of CMOF crystals.

[0050] Furthermore, the regulator includes at least one of glacial acetic acid, acetic acid, formic acid, lauric acid, or sodium formate. In addition to these listed regulators, other common regulators of crystallization reactions are also within the scope of this application.

[0051] In some embodiments, the solvent is a polar solvent with a dielectric constant ≥30 at 25°C.

[0052] The polar solvents include at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide. In addition to these listed solvents, other strongly polar solvents with a dielectric constant ≥30 are also within the scope of protection of this application.

[0053] In some embodiments, the concentration of the organic ligand in the mixture is 1-2 wt% (e.g., 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, or 2 wt%, but not limited to the listed values; other unlisted values ​​within the above range are also applicable). The mass ratio of the added organic ligand, the metal salt, and the regulator is 1:(1-2.2):(5-7.5) (e.g., 1:1:5, 1:1.4:5.5, 1:1.6:5.8, 1:1.8:6, 1:1.9:6.5, 1:2:7, 1:2.1:6.5, or 1:2.2:7.5, but not limited to the listed values; other unlisted values ​​within the above range are also applicable). Preferably, in the mixture, the concentration of the organic ligand is 1.2-1.7 wt%, and the mass ratio of the added organic ligand, the metal salt, and the regulator is 1:(1.4-1.9):(5.8-7).

[0054] In some embodiments, metal salts and organic ligands are added to a solvent, and after being fully dispersed and dissolved, a modifier is added to form a mixture.

[0055] In some embodiments, the mixture is heated to 100-140°C (e.g., 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, or 140°C, but not limited to the listed values; other unlisted values ​​within the above range are also applicable.), and a crystallization reaction is carried out for 15-20 hours (e.g., 15 hours, 15.5 hours, 16 hours, 16.5 hours, 17 hours, 17.5 hours, 18 hours, 18.5 hours, 19 hours, 19.5 hours, or 20 hours, but not limited to the listed values; other unlisted values ​​within the above range are also applicable.), to generate crystalline metal-organic framework particles (crystalline CMOF particles).

[0056] In some embodiments, in step S2, the purified crystalline metal-organic framework particles are vacuum activated at 90-110°C (e.g., 90°C, 95°C, 100°C, 105°C, 110°C, but not limited to the listed values; other unlisted values ​​within the above range are also applicable) for 8-12 hours (e.g., 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 10.5 hours, 11 hours, 11.5 hours, or 12 hours, but not limited to the listed values; other unlisted values ​​within the above range are also applicable) to obtain a powdered crystalline CMOF catalyst.

[0057] In some embodiments, the step of purifying crystalline CMOF particles is as follows: the solution containing crystalline CMOF particles in S1 is centrifuged, the precipitate is collected, and washed sequentially with the solvent and an alcohol solvent. Then, the precipitate is replaced in an alcohol solvent for 10-14 hours (e.g., 10h, 10.5h, 11h, 11.5h, 12h, 12.5h, 13h, 13.5h, or 14h, but not limited to the listed values; other unlisted values ​​within the above range are also applicable), to obtain purified crystalline CMOF particles.

[0058] The alcohol solvents include at least one of anhydrous ethanol, methanol, isopropanol, n-butanol, cyclohexanol, ethylene glycol, or propylene glycol. In addition to these listed alcohol solvents, other common alcohol solvents are also within the scope of protection of this application.

[0059] A second aspect of this application provides a crystalline CMOF catalyst for the contact electrocatalytic removal of water pollutants, wherein the crystalline CMOF catalyst is obtained by the above-described preparation method.

[0060] In some embodiments, the particle size of the crystalline CMOF catalyst is 50 nm to 5 μm (e.g., 50 nm, 80 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm, but not limited to the listed values; other unlisted values ​​within the above range are also applicable). Preferably, the particle size of the crystalline CMOF catalyst is 100 nm to 4 μm. Preferably, the particle size of the crystalline CMOF catalyst is 500 nm to 3.5 μm. Preferably, the particle size of the crystalline CMOF catalyst is 800 nm to 3 μm.

[0061] In some embodiments, the pore size of the crystalline CMOF catalyst is 0.5-10 nm (e.g., 0.5 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm, but not limited to the listed values; other unlisted values ​​within the above range are also applicable). Preferably, the pore size of the crystalline CMOF catalyst is 0.8-9.5 nm. Preferably, the pore size of the crystalline CMOF catalyst is 1-9 nm. Preferably, the pore size of the crystalline CMOF catalyst is 2-8 nm. Preferably, the pore size of the crystalline CMOF catalyst is 3-7 nm.

[0062] Compared to conventional MOF adsorption systems, the crystalline CMOF in this application, used as a catalyst in contact electrocatalysis, enhances interfacial potential drive through a contact electrocatalysis process. Leveraging the ordered metal nodes and regular pore structure of the CMOF, organic pollutants are enriched at the pores and interfaces, providing mass transfer channels. Charge transfer and in-situ generation of reactive oxygen species occur near the metal nodes of the crystalline CMOF, improving electron migration efficiency, reactive oxygen species generation efficiency, and pollutant enrichment capacity. This results in highly efficient removal of organic pollutants under low energy consumption. Furthermore, this application does not involve post-metallization / secondary introduction of metal sites; the catalytic active center originates from the crystalline CMOF structure itself.

[0063] Metal-organic frameworks (MOFs) can include crystalline materials as well as framework materials with low crystallinity, numerous defects, or local disorder. The crystalline CMOF of this application is a crystalline metal-organic framework material with a characterizable ordered crystalline structure, regular channels, and a well-defined distribution of metal nodes. The main differences between the crystalline CMOF of this application and conventional MOFs (amorphous) are: the spatial distribution of metal nodes in the crystalline CMOF is more ordered, and the active sites are more uniform; the pore structure is more regular, which is more conducive to the enrichment and mass transfer of organic pollutants; and the crystalline framework is more likely to maintain structural stability and reusability in an ultrasound-induced contact-separation environment.

[0064] A third aspect of this application discloses a method for using crystalline CMOF catalysts in contact electrocatalytic removal of water pollutants, comprising the following steps: A1, the above-mentioned crystalline CMOF catalyst is mixed with an aqueous solution containing organic pollutants to form a solid-liquid reaction system; or the above-mentioned crystalline CMOF catalyst is fixed on a conductive substrate as a catalyst layer; A2, applying a force to the solid-liquid reaction system or the catalyst layer to trigger a contact electrocatalytic process, generating reactive oxygen groups, and the organic pollutants are degraded under the action of the reactive oxygen groups.

[0065] The mechanism of action of the crystalline CMOF catalyst in the contact electrocatalytic removal of organic pollutants in water can be summarized as a process of "pore enrichment - contact electrification - ordered metal node activation - interfacial oxidative degradation". First, the crystalline CMOF catalyst is formed by the direct coordination assembly of metal ions or metal cluster nodes with organic ligands. The metal nodes in the framework are distributed in a crystalline, ordered manner and serve as intrinsic catalytic active centers. The regular channels can adsorb and enrich organic pollutant molecules and shorten their diffusion distance to the active sites. Second, under ultrasonic action, the crystalline CMOF catalyst continuously contacts and separates with the liquid microenvironment, between particles, or between particles and the substrate, generating a contact electrification effect and forming a transient interfacial potential difference. Third, this potential difference drives the redistribution of electrons between the crystalline framework and the metal nodes, improving the activation ability of the metal nodes for dissolved oxygen and water molecules, thereby generating active oxygen groups (…). · OH, O2 ·- (etc.). Then, because organic pollutants are enriched in the pore and interface regions, reactive oxygen groups can continuously oxidize and degrade them in the short term, achieving efficient removal and good cycle stability.

[0066] In some embodiments, in step A1, the concentration of the crystalline CMOF catalyst in the solid-liquid reaction system is 200-300 mg / L, such as 200 mg / L, 210 mg / L, 220 mg / L, 230 mg / L, 240 mg / L, 250 mg / L, 260 mg / L, 270 mg / L, 280 mg / L, 290 mg / L, or 300 mg / L, but not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0067] In some embodiments, in step A2, the applied force includes at least one of: ultrasound, mechanical vibration, liquid flow impact, stirring shear, or gas-liquid disturbance.

[0068] Furthermore, the ultrasonic treatment power is 80-150W (e.g., 80W, 90W, 100W, 110W, 120W, 130W, 140W, or 150W, but not limited to the listed values; other unlisted values ​​within the above range also apply.), the frequency is 20-80kHz (e.g., 20kHz, 25kHz, 30kHz, 35kHz, 40kHz, 45kHz, 50kHz, 55kHz, 60kHz, 65kHz, 70kHz, 75kHz, or 80kHz, but not limited to the listed values; other unlisted values ​​within the above range also apply.), and the temperature of the solid-liquid reaction system during ultrasonic treatment is 23-27℃ (e.g., 23℃, 24℃, 25℃, 26℃, or 27℃, but not limited to the listed values; other unlisted values ​​within the above range also apply.).

[0069] Furthermore, the active oxygen group includes: hydroxyl radical ( · OH), or superoxide anion radical (O2) ·- At least one of the following.

[0070] Furthermore, the organic pollutants include at least one of the following: ibuprofen (IBU), norfloxacin (NOR), bisphenol A (BPA), sulfadimidine (SDZ), ornidazole, azo dyes, rhodamine B, or methyl orange. In addition to these listed organic pollutants, other common organic pollutants are also within the scope of protection of this application.

[0071] In some embodiments, after the degradation reaction is completed, solid-liquid separation is achieved by sedimentation, filtration or centrifugation to recover the crystalline CMOF catalyst; after washing and drying, it can be reused for the next degradation of water pollutants to achieve multiple cycles of treatment, wherein the multiple cycles are ≤6 times.

[0072] The crystalline CMOF catalyst of this application is used for contact electrocatalytic removal of water pollutants. Experimental verification shows that after 60 minutes of sonication, the degradation rate of ibuprofen (IBU), norfloxacin (NOR), and bisphenol A (BPA) can reach 100%. After the crystalline CMOF catalyst is recycled 6 times, there is no significant change in the removal efficiency of these three organic pollutants. The crystalline CMOF catalyst has excellent stability and can be reused multiple times.

[0073] The present application will be further described in detail below with reference to specific embodiments and comparative examples. However, the present application is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use. The conditions not specified are conventional conditions in the industry.

[0074] Example 1: Preparation of crystalline CMOF catalyst At room temperature (25℃), 0.54 g of FeCl3·6H2O, 0.33 g of terephthalic acid (BDC), and 40 mL of N,N-dimethylformamide (DMF) were added to a beaker. The mixture was stirred at 400 rpm for 10 min to ensure complete dispersion and dissolution. Then, 2.0 mL of glacial acetic acid was added and mixed thoroughly. The mixture was then transferred to a 50 mL polytetrafluoroethylene-lined reactor. The reactor was heated to 120℃ and reacted for 18 h.

[0075] After the reactor was cooled to room temperature, the reaction mixture was centrifuged (8000 rpm, 5 min) to collect the solid precipitate. The precipitate was then washed three times each with N,N-dimethylformamide (DMF) and anhydrous ethanol (30 mL each time, soaking for 30 min), followed by displacement in anhydrous ethanol for 12 h. Finally, the catalyst was activated under vacuum at 100 °C for 10 h to obtain the crystalline CMOF catalyst.

[0076] Example 2: Preparation of crystalline CMOF catalyst copper nitrate trihydrate At room temperature (25℃), 0.6 g of copper nitrate trihydrate, 0.33 g of terephthalic acid (BDC), and 40 mL of N,N-dimethylacetamide were added to a beaker and stirred at 400 rpm for 10 min to ensure complete dispersion and dissolution. Then, 2.2 mL of glacial acetic acid was added and mixed thoroughly. The mixture was then transferred to a 50 mL polytetrafluoroethylene-lined reactor. The reactor was heated to 125℃ and reacted for 17 h.

[0077] After the reactor was cooled to room temperature, the reaction mixture was centrifuged (8000 rpm, 5 min) to collect the solid precipitate. The precipitate was then washed three times each with N,N-dimethylacetamide and anhydrous ethanol (30 mL each time, soaking for 30 min). Subsequently, it was replaced with anhydrous ethanol for 13 h. Finally, it was activated under vacuum at 100 °C for 11 h to obtain the crystalline CMOF catalyst.

[0078] Example 3: Degradation of Ibuprofen (IBU) In a 40 mL glass bottle, the crystalline CMOF catalyst prepared in Example 1 and water containing ibuprofen (IBU) contaminants were added and mixed. The initial concentration of the crystalline CMOF catalyst was 250 mg / L, and the initial concentration of IBU was 10 mg / L. The glass bottle was placed in an ultrasonic cleaner with an ultrasonic power of 110 W, a frequency of 40 kHz, and a temperature of 25 °C. Samples were taken at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min to measure the degradation effect of IBU. The degradation effect of the crystalline CMOF catalyst on IBU is shown in the figure below. Figure 1 As shown. Among them, the appendix Figure 1-8 The ordinate C in t / C0 represents the residual rate of organic pollutants, C t Ct refers to the concentration of a certain organic pollutant in the solution at time t, and C0 refers to the initial concentration of the organic pollutant.

[0079] exist Figure 1 During the reaction, at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min, the remaining IBU was 0.752, 0.504, 0.201, 0.043, 0.0220, and 0, respectively, meaning the degradation rates of IBU were 24.8%, 49.6%, 79.9%, 95.7%, 97.8%, and 100%, respectively. Figure 1 As can be seen from the remaining rate data, the crystalline CMOF catalyst of this application can achieve a 100% degradation rate of ibuprofen after 60 minutes of ultrasonic treatment.

[0080] Example 4: Repeated experiment to degrade ibuprofen (IBU) In Example 3, after the degradation reaction was completed, solid-liquid separation was achieved by centrifugation. The catalyst was washed three times each with N,N-dimethylformamide (DMF) and anhydrous ethanol. Then, it was dried under vacuum at 60°C for 12 hours to recover the crystalline CMOF catalyst. The recovered crystalline CMOF catalyst and water containing ibuprofen (IBU) contaminants were added to a 40 mL glass bottle. The initial concentration of the recovered crystalline CMOF catalyst was 250 mg / L, and the initial concentration of IBU was 10 mg / L. The glass bottle was placed in an ultrasonic cleaner with an ultrasonic power of 110 W, a frequency of 40 kHz, and a temperature of 25°C. Samples were taken at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min to determine the degradation effect of IBU.

[0081] The recovered crystalline CMOF catalyst was then used in the contact electrocatalytic removal of IBU contaminants from water, and this process was repeated four times. That is, Examples 3 and 4 involved a total of six repetitions of the crystalline CMOF catalyst. The degradation effect on IBU is shown in the graph. Figure 2 As shown.

[0082] Depend on Figure 2 It is evident that the crystalline CMOF catalyst of this application, when applied to the electrocatalytic removal of IBU contaminants from water via contact electrocatalysis, achieves a 100% degradation rate after 60 minutes of ultrasonication. Furthermore, the crystalline CMOF catalyst was recovered and recycled five times, showing no significant difference in its IBU degradation performance, maintaining a 100% removal efficiency even after 60 minutes of ultrasonication. This crystalline CMOF catalyst demonstrates highly efficient pollutant degradation performance and excellent stability.

[0083] Example 5: Degradation of Norfloxacin (NOR) In a 40 mL glass bottle, the crystalline CMOF catalyst prepared in Example 1 and water containing norfloxacin (NOR) contaminant were added and mixed. The initial concentration of the crystalline CMOF catalyst was 250 mg / L, and the initial concentration of NOR was 10 mg / L. The glass bottle was placed in an ultrasonic cleaner with an ultrasonic power of 110 W, a frequency of 40 kHz, and a temperature of 25 °C. Samples were taken at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min to measure the degradation effect of NOR. The degradation effect of the crystalline CMOF catalyst on NOR is shown in the figure below. Figure 3 As shown.

[0084] exist Figure 3 During the reaction, at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min, the remaining NOR percentages were 0.754, 0.5016, 0.208, 0.083, 0.025, and 0, respectively, meaning the NOR degradation rates were 24.6%, 49.8%, 79.2%, 91.7%, 97.5%, and 100%, respectively. Figure 3 As can be seen from the remaining rate data, the crystalline CMOF catalyst of this application can achieve a 100% degradation rate of norfloxacin after 60 minutes of ultrasonic treatment.

[0085] Example 6: Repeated experiment to degrade norfloxacin (NOR) In Example 5, after the degradation reaction was completed, solid-liquid separation was achieved by centrifugation. The catalyst was washed three times each with N,N-dimethylformamide (DMF) and anhydrous ethanol. Then, it was dried under vacuum at 60°C for 12 hours to recover the crystalline CMOF catalyst. The recovered crystalline CMOF catalyst and water containing norfloxacin (NOR) contaminants were added to a 40 mL glass bottle. The initial concentration of the recovered crystalline CMOF catalyst was 250 mg / L, and the initial concentration of NOR was 10 mg / L. The glass bottle was placed in an ultrasonic cleaner with an ultrasonic power of 110 W, a frequency of 40 kHz, and a temperature of 25°C. Samples were taken at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min to determine the NOR degradation effect.

[0086] The recovered crystalline CMOF catalyst was then used in the contact electrocatalytic removal of NOR contaminants from water, and this process was repeated four times. That is, Examples 5 and 6 involved a total of six repeated uses of the crystalline CMOF catalyst. The degradation effect on NOR is shown in the graph. Figure 4 As shown.

[0087] Depend on Figure 4It is evident that the crystalline CMOF catalyst of this application, when applied to the electrocatalytic removal of NOR contaminants from water, achieves a 100% degradation rate after 60 minutes of ultrasonication. Furthermore, the crystalline CMOF catalyst was recovered and recycled five times, showing no significant difference in its NOR degradation performance; the NOR removal efficiency remained at 100% after 60 minutes of ultrasonication. This crystalline CMOF catalyst exhibits highly efficient pollutant degradation performance and excellent stability.

[0088] Example 7: Degradation of Bisphenol A (BPA) In a 40 mL glass bottle, the crystalline CMOF catalyst prepared in Example 2 and water containing bisphenol A (BPA) contaminant were added and mixed. The initial concentration of the crystalline CMOF catalyst was 250 mg / L, and the initial concentration of BPA was 10 mg / L. The glass bottle was placed in an ultrasonic cleaner with an ultrasonic power of 110 W, a frequency of 40 kHz, and a temperature of 25 °C. Samples were taken at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min to measure the degradation effect of BPA. The degradation effect of the crystalline CMOF catalyst on BPA is shown in the figure below. Figure 5 As shown.

[0089] exist Figure 5 During the reaction, at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min, the remaining percentages of BPA were 0.781, 0.512, 0.248, 0.106, 0.041, and 0, respectively, meaning the degradation rates of BPA were 21.9%, 48.8%, 75.2%, 89.4%, 95.9%, and 100%, respectively. Figure 5 As can be seen from the residual rate data, the crystalline CMOF catalyst of this application can achieve a 100% degradation rate of bisphenol A after 60 minutes of sonication.

[0090] Example 8: Repeated experiment to degrade bisphenol A (BPA) In Example 7, after the degradation reaction was completed, solid-liquid separation was achieved by centrifugation. The catalyst was washed three times each with N,N-dimethylformamide (DMF) and anhydrous ethanol. Then, it was dried under vacuum at 60°C for 12 hours to recover the crystalline CMOF catalyst. The recovered crystalline CMOF catalyst and water containing bisphenol A (BPA) contaminant were added to a 40 mL glass bottle. The concentration of the recovered initial crystalline CMOF catalyst was 250 mg / L, and the initial BPA concentration was 10 mg / L. The glass bottle was placed in an ultrasonic cleaner with an ultrasonic power of 110 W, a frequency of 40 kHz, and a temperature of 25°C. Samples were taken at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min to determine the BPA degradation effect.

[0091] The recovered crystalline CMOF catalyst was then used in the contact electrocatalytic removal of BPA contaminants from water, and this process was repeated four times. That is, Examples 7 and 8 involved a total of six repetitions of the crystalline CMOF catalyst. The degradation effect on BPA is shown in the graph. Figure 6 As shown.

[0092] Depend on Figure 6 It is evident that the crystalline CMOF catalyst of this application, when applied to the contact electrocatalytic removal of BPA contaminants from water, achieves a degradation rate of 100% after 60 minutes of ultrasonication. Furthermore, the crystalline CMOF catalyst was recovered and recycled five times, showing no significant difference in its BPA degradation performance; the BPA removal efficiency remained at 100% after 60 minutes of ultrasonication. This crystalline CMOF catalyst exhibits highly efficient pollutant degradation performance and excellent stability.

[0093] Comparative Example 1: Degradation of Ibuprofen (IBU) by Polyvinylidene Fluoride (PVDF) Polyvinylidene fluoride (PVDF) and water containing ibuprofen (IBU) were added to a 40 mL glass bottle. The initial concentration of PVDF was 250 mg / L, and the initial concentration of IBU was 10 mg / L. The glass bottle was placed in an ultrasonic cleaner with an ultrasonic power of 110 W, a frequency of 40 kHz, and a temperature of 25 °C. Samples were taken at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min to measure the degradation effect of IBU. The degradation effect of PVDF on IBU is shown in the figure below. Figure 7 As shown.

[0094] exist Figure 7 During the reaction, at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min, the remaining IBU percentages were 0.861, 0.724, 0.592, 0.481, 0.423, and 0.371, respectively, meaning the IBU degradation rates were 13.9%, 27.6%, 40.8%, 51.9%, 57.7%, and 62.9%, respectively. Figure 7 According to the residual rate data, the degradation rate of ibuprofen by polyvinylidene fluoride is 62.9% after 60 minutes of ultrasonic treatment.

[0095] Comparative Example 2: Repeated experiments with polyvinylidene fluoride (PVDF) to degrade ibuprofen (IBU). After the degradation reaction in Comparative Example 1 was completed, solid-liquid separation was achieved by centrifugation. The mixture was washed three times each with dimethyl sulfoxide (DMSO) and anhydrous ethanol. Then, it was dried under vacuum at 60°C for 12 hours to recover polyvinylidene fluoride (PVDF). The recovered PVDF and water containing ibuprofen (IBU) were added to a 40 mL glass bottle. The initial concentration of the recovered PVDF was 250 mg / L, and the initial concentration of IBU was 10 mg / L. The glass bottle was placed in an ultrasonic cleaner with an ultrasonic power of 110 W, a frequency of 40 kHz, and a temperature of 25°C. Samples were taken at reaction times of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min to determine the degradation effect of IBU.

[0096] The recovered polyvinylidene fluoride was then used in the contact electrocatalytic removal of IBU contaminants from water, and this process was repeated four times. In other words, Comparative Examples 1 and 2 involved a total of six repetitions of polyvinylidene fluoride. The degradation effect on IBU is shown in the graph. Figure 8 As shown.

[0097] Depend on Figure 8 It was found that when polyvinylidene fluoride (PVDF) was applied to the contact electrocatalytic removal of IBU contaminants in water, the degradation rate was 62.9% after 60 minutes of ultrasonication. After recycling and reusing the PVDF five times, the residual IBU (Ct / C0) after 60 minutes of ultrasonication was approximately 0.36-0.40, corresponding to a degradation rate of 60%-64%. This indicates that the contact electrocatalytic activity of PVDF is significantly lower than that of the crystalline CMOF catalyst described in this application.

[0098] Although this application discloses several aspects and embodiments, other aspects and embodiments will be obvious to those skilled in the art. Various modifications and improvements can be made without departing from the concept of this application, and these all fall within the scope of protection of this application. The various aspects and embodiments disclosed in this application are for illustrative purposes only and are not intended to limit this application. The actual scope of protection of this application is determined by the claims.

Claims

1. A method for preparing a crystalline CMOF catalyst for the electrocatalytic removal of water pollutants, characterized in that, Including the following steps: S1, metal salt, organic ligand, regulator and solvent are mixed evenly to form a mixture, and crystallization reaction is carried out to generate crystalline metal-organic framework particles; S2, the crystalline metal-organic framework particles are purified and then activated under vacuum to open the pores of the crystalline metal-organic framework particles, thereby obtaining a crystalline metal-organic framework catalyst.

2. The method for preparing the crystalline CMOF catalyst for contact electrocatalytic removal of water pollutants as described in claim 1, characterized in that, Includes one or more features selected from the following group: (1) The metal salt includes at least one of the following: iron salt, copper salt, cobalt salt, nickel salt, zirconium salt, or titanium salt; (2) The organic ligand is an acidic organic ligand; the acidic organic ligand includes at least one of terephthalic acid, aminoterephthalic acid, pyromellitic acid, nitrogen-containing polydentate acidic organic ligand, isophthalic acid, or phthalic acid; (3) The regulator is used to control the nucleation and growth rate of CMOF crystals; the regulator includes at least one of glacial acetic acid, acetic acid, formic acid, lauric acid, or sodium formate; (4) The solvent is a polar solvent, and the dielectric constant of the polar solvent at 25°C is ≥30.

3. The method for preparing the crystalline CMOF catalyst for contact electrocatalytic removal of water pollutants as described in claim 1, characterized in that, In the mixture, the concentration of the organic ligand is 1-2 wt%, and the mass ratio of the added organic ligand, the metal salt, and the regulator is 1:(1-2.2):(5-7.5).

4. The method for preparing the crystalline CMOF catalyst for contact electrocatalytic removal of water pollutants as described in claim 1, characterized in that, The mixture is heated to 100-140℃ and crystallized for 15-20 hours to generate crystalline metal-organic framework particles.

5. The method for preparing the crystalline CMOF catalyst for contact electrocatalytic removal of water pollutants as described in claim 1, characterized in that, In step S2, the purified crystalline metal-organic framework particles are activated under vacuum at 90-110℃ for 8-12 hours to obtain a powdered crystalline CMOF catalyst.

6. A crystalline CMOF catalyst for the electrocatalytic removal of water pollutants, characterized in that, The crystalline CMOF catalyst is obtained by any of the preparation methods described in claims 1-5.

7. The crystalline CMOF catalyst for contact electrocatalytic removal of water pollutants as described in claim 6, characterized in that, The crystalline CMOF catalyst has a particle size of 50 nm-5 μm; the pore size of the crystalline CMOF catalyst is 0.5-10 nm.

8. A method for applying crystalline CMOF catalysts in the electrocatalytic removal of water pollutants, characterized in that, Including the following steps: A1, the crystalline CMOF catalyst obtained by any of the preparation methods described in claims 1-5 or the crystalline CMOF catalyst described in claims 6-7, is mixed with an aqueous solution containing organic pollutants to form a solid-liquid reaction system; or the above-mentioned crystalline CMOF catalyst is fixed on a conductive substrate as a catalyst layer; A2, applying a force to the solid-liquid reaction system or the catalyst layer to trigger a contact electrocatalytic process, generating reactive oxygen groups, and the organic pollutants are degraded under the action of the reactive oxygen groups.

9. The method for applying the crystalline CMOF catalyst as described in claim 8 in the contact electrocatalytic removal of water pollutants, characterized in that, In step A1, the concentration of the crystalline CMOF catalyst in the solid-liquid reaction system is 200-300 mg / L; in step A2, the applied force includes at least one of: ultrasound, mechanical vibration, liquid flow impact, stirring shear, or gas-liquid disturbance; the organic pollutant includes at least one of: ibuprofen, norfloxacin, bisphenol A, sulfadiazine, ornidazole, azo dye, rhodamine B, or methyl orange.

10. The method for applying the crystalline CMOF catalyst as described in claim 8 in the contact electrocatalytic removal of water pollutants, characterized in that, After the degradation reaction is completed, solid-liquid separation is achieved by sedimentation, filtration or centrifugation to recover the crystalline CMOF catalyst. After washing and drying, it can be reused for the next degradation of water pollutants to achieve multiple cycles of treatment, wherein the multiple cycles are ≤6 times.

Images