MOF (Metal Organic Framework)-based material for synchronously removing organic matters and heavy metals in waste salt as well as preparation method and application of MOF-based material

Abstract

The invention discloses an MOF-based material for synchronously removing waste salt organic matters and heavy metals as well as a preparation method and application of the MOF-based material, and belongs to the technical field of photocatalysts. The technical problem to be solved is to realize simultaneous removal of heavy metal ions and organic pollutants and improve the photocatalytic performance and recyclability of the existing MOF-based material. According to the technical scheme, the preparation method of the MOF-based material is characterized by comprising the following steps: (1) preparing MIL-125-NH2; (2) compounding MIL-101-NH2 on the MIL-125-NH2 obtained in the step (1), so as to obtain an MOF (Metal Organic Framework) compound; and (3) loading an indium catalyst on the MOF compound prepared in the step (2) to obtain the MOF-based material.

Description

Technical Field

[0001] This invention relates to the field of photocatalyst technology, specifically to a MOF-based material for the simultaneous removal of waste salt organic matter and heavy metals, its preparation method, and its application. Background Technology

[0002] The persistent organic pollutants and toxic heavy metals in waste salt pose a serious threat to ecological security and human health. There is an urgent need for an efficient and green impurity removal technology to remove pollutants and efficiently reuse waste salt as a resource.

[0003] Common methods for treating organic matter include electrochemical methods, membrane separation methods, advanced oxidation methods, chemical precipitation methods, adsorption methods, coagulation methods, and pyrolysis methods. Among these, adsorption methods have advantages such as simple operation, low cost, and high efficiency, and are used for the deep purification of heavy metals and organic matter in waste salt and high-salinity wastewater. Photocatalysis technology is considered one of the most promising technologies for removing organic pollutants due to its green, environmentally friendly, and pollution-free characteristics. Therefore, researching the synergistic removal of heavy metals and organic matter from wastewater by adsorption and photocatalysis, simultaneously detoxifying and concentrating heavy metals while mineralizing organic matter into CO2 and H2O, is of great significance for improving the purification efficiency of waste salt solutions.

[0004] Adsorbents used for the removal of heavy metal ions include carbon materials (activated carbon, biochar, carbon nanotubes, etc.), metal-organic frameworks (MOFs), polymeric synthetic adsorbents (resins, etc.), and bioadsorbents (bacteria, fungi, algae, etc.). Among them, MOFs have attracted widespread attention in the fields of pollutant adsorption and photocatalysis due to their advantages such as high specific surface area, tunable structure, and diverse functions.

[0005] Relevant patent documents retrieved: The patent document, published in China (CN118807838A) on October 22, 2024, discloses a foam metal-based photocatalytic material capable of simultaneously degrading antibiotics and reducing Cu(II), its preparation method, and its application. The invention first grows photocatalytically active metal selenides in situ on the surface of foam metal, and then anchors Zn / Co-MOF5 nanoparticles on its surface, further forming pn heterojunctions to achieve simultaneous degradation of enrofloxacin and reduction of Cu(II) in wastewater.

[0006] Relevant non-patent literature retrieved: The journal title is "Master's Thesis of Jiangxi University of Science and Technology," and the document title is "Performance Study of Photocatalytic Degradation of Organic Pollutants by MOF-In2S3-based Composite Materials." The publication date is May 22, 2024. This non-patent document discloses a ZnFe-LDO / MOF-In2S3 composite material. Under visible light irradiation for 25 minutes, this composite material exhibits visible light photocatalytic degradation efficiencies of 92% and 80% for tetracycline hydrochloride and oxytetracycline, respectively. Furthermore, after four cycles, its photocatalytic degradation efficiency stabilizes above 70%.

[0007] The prior art represented by the aforementioned documents has at least the following unresolved technical problems or defects: Although the foam metal-based photocatalytic material provided in the patent document can simultaneously degrade enrofloxacin and reduce Cu(II) in wastewater, its catalytic degradation efficiency decreases significantly after repeated use, and its recycling performance is poor.

[0008] Although the non-patent literature improved the recyclability of the composite material to some extent, there is still room for improvement in its recyclability, and the composite material cannot achieve the simultaneous removal of heavy metal ions and organic pollutants. Summary of the Invention

[0009] The purpose of this invention is to provide: A MOF-based material for the simultaneous removal of organic matter and heavy metals from waste salts, and related technologies, to solve the technical problems of poor recyclability of existing MOF-based materials, and the inability to simultaneously remove heavy metal ions and organic pollutants or a combination thereof.

[0010] Terminology Explanation: Unless otherwise defined, all technical terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this subject matter pertains. Unless otherwise stated, all patents, patent inventions, and disclosures cited throughout this document are incorporated herein by reference in their entirety. Where multiple definitions exist for terms herein, the definitions provided in this chapter shall prevail.

[0011] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0012] The definition of the standard chemical term can be found in the reference "Construction and Photocatalytic Performance of MOFs-Semiconductor Heterostructures", authors: Fang Yongzheng, Zhang Na, Zhang Jianyong, Shanghai Jiaotong University Press, published in 2022.

[0013] Unless otherwise specified, conventional methods within the scope of the art shall be used, such as solution preparation, homogeneous reaction, centrifugation, washing, drying, material characterization and performance testing (scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy), photocatalytic degradation of pollutants, and kinetic fitting of material to pollutant degradation.

[0014] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various general and more specific documents cited and discussed in this specification.

[0015] The term “MIL-125-NH2” used in this article, also written as NH2-MIL-125(Ti), is an amino-functionalized metal-organic framework material with titanium as the metal node and 2-aminoterephthalic acid as the organic ligand. It has a high specific surface area, tunable pore structure and good chemical stability, and is widely used in photocatalysis, gas adsorption, biomedicine and other fields.

[0016] The term "MIL-101-NH2" used in this article refers to a metal-organic framework (MOF) material, belonging to the amino-functionalized derivatives of the MIL-101 series. It is a three-dimensional porous structure formed by the self-assembly of metal ions (such as chromium, aluminum, or iron) and organic ligands (usually terephthalic acid or its amino-modified version). "NH2" indicates the introduction of amino functional groups into the structure, which enhances the material's adsorption capacity and chemical stability. This material possesses a high specific surface area, tunable pore structure, and good thermal and chemical stability, thus showing broad application prospects in adsorption, catalysis, gas storage, and environmental remediation. For example, it can be used to adsorb organic pollutants (such as naproxen) or heavy metal ions in water, often exhibiting superior adsorption performance compared to unfunctionalized MIL-101. Different metal-based MIL-101-NH2 (such as MIL-101(Cr)-NH2, MIL-101(Al)-NH2, or MIL-101(Fe)-NH2) may differ slightly in specific properties and applications, but their core structures are similar.

[0017] The term "composite" as used in this article refers to a material design and preparation strategy that combines two or more basic units with different compositions (such as semiconductor-semiconductor, semiconductor-metal, semiconductor-carbon materials, etc.), different structures, or different functions (such as photoresponse units, co-catalytic units, and support units) into one unit through physical doping, chemical bonding, interface assembly, etc., in order to achieve synergistic effects among the basic units and thereby improve the performance defects of single photocatalytic materials in terms of light absorption, charge separation, and catalytic activity.

[0018] The term "loading" as used in this article refers to a material modification process in which one or more active components with specific functions (such as metal nanoparticles, co-catalysts, quantum dots, etc.) are fixed onto the surface or pores of a support material (such as semiconductor matrix, carbon material, molecular sieve, etc.) with a high specific surface area and stable structure through physical adsorption, chemical deposition, chemical bonding, in-situ growth, etc. The purpose is to improve the dispersibility and utilization rate of the active components, enhance the interfacial interaction between the active components and the support, and thus improve the photocatalytic performance of the composite material.

[0019] The term "photocatalytic reaction" used in this article refers to a series of redox reactions initiated by photocatalytic materials using light as the energy input source. Specifically, after the photocatalytic material absorbs photon energy equal to or greater than its band gap, valence band electrons are excited and jump to the conduction band, forming photogenerated electron-hole pairs. These charge carriers migrate to the material surface and react with adsorbed reactants (such as organic pollutants, water molecules, oxygen, etc.) to achieve the target processes of pollutant degradation, hydrogen production, and carbon dioxide reduction. This reaction usually takes place at room temperature and pressure, and has the characteristics of low energy consumption and environmental friendliness.

[0020] In a first aspect, the present invention provides: a method for preparing a MOF-based material, comprising the steps of: (1) preparing MIL-125-NH2; (2) compounding MIL-101-NH2 on the MIL-125-NH2 prepared in step (1) to obtain a MOF composite; and (3) loading an indium catalyst onto the MOF composite prepared in step (2) to obtain the MOF-based material.

[0021] Among them, the technical features include: MIL-125-NH2, composite, MIL-101-NH2 composite, and indium catalyst.

[0022] The preparation method of MIL-125-NH2 in step (1) is as follows: titanium compound and 2-aminoterephthalic acid are subjected to homogeneous reaction in an organic solvent. After the reaction, the precipitate is washed and dried to obtain MIL-125-NH2.

[0023] The titanium compound is preferably at least one of tetrabutyl titanate, titanium tetrachloride, titanium oxysulfate, and tetraethyl titanate.

[0024] The titanium compound is further preferably at least one of tetrabutyl titanate and tetraethyl titanate.

[0025] The titanium compound is more preferably tetrabutyl titanate.

[0026] The organic solvent is selected from at least one of DMF, MeOH, EtOH, H2O and 1,4-dioxane.

[0027] The organic solvent is preferably at least one of DMF, MeOH, EtOH and 1,4-dioxane.

[0028] The organic solvent is further preferably at least one of DMF, MeOH, and EtOH.

[0029] A further preferred embodiment is the use of a combination of DMF and MeOH; Preferably, the volume ratio of DMF to MeOH is 12:1-6:1; A further preferred ratio is 10:1 to 8:1; An even better option is 9:1.

[0030] The ratio of the amount of the titanium compound, 2-aminoterephthalic acid, and organic solvent is selected from the following: 0.9-0.4 mL : 0.78-0.34 g : 60-20 mL.

[0031] The preferred ratio of the amount of the titanium compound, 2-aminoterephthalic acid, and organic solvent is: 0.7-0.5 mL : 0.67-0.45 g : 50-30 mL.

[0032] The preferred ratio of the amounts of the titanium compound, 2-aminoterephthalic acid, and organic solvent is 0.6 mL: 0.56 g: 40 mL.

[0033] The homogeneous reaction conditions are selected from: temperature 170-130℃; heating rate 5-15℃ / min; reaction time 26-22 hours.

[0034] The preferred homogeneous reaction conditions are: temperature 160-140℃; heating rate 5-10℃ / min; reaction time 26-23 hours.

[0035] The preferred homogeneous reaction conditions are: temperature 150℃; heating rate 5℃ / min; reaction time 24 hours.

[0036] The composite method described in step (2) is as follows: the MIL-125-NH2 prepared in step (1) is mixed with a solution containing iron salt, 2-aminoterephthalic acid and N,N-dimethylformamide for homogeneous reaction. After the reaction, the precipitate is washed and dried to obtain the MIL-101-NH2 complex.

[0037] The iron salt is preferably at least one of ferric chloride hexahydrate, ferric nitrate nonahydrate, and ferric sulfate.

[0038] The iron salt is further preferably at least one of ferric chloride hexahydrate and ferric nitrate nonahydrate.

[0039] The iron salt is more preferably ferric chloride hexahydrate.

[0040] The solvent of the solution is selected from at least one of DMF, methanol, ethanol and water.

[0041] The solvent of the solution is preferably at least one of DMF, methanol, ethanol and water.

[0042] The solvent of the solution is further preferably at least one of DMF, methanol, and ethanol.

[0043] The solvent for the solution is more preferably DMF.

[0044] The ratio of the amount of iron salt, 2-aminoterephthalic acid and solvent in the solution is selected from the following: 8-2 mmol: 5.5-0.5 mmol: 70-40 mL.

[0045] The preferred ratio of the amounts of iron salt, 2-aminoterephthalic acid, and solvent in the solution is 6-4 mmol: 3.5-2 mmol: 60-50 mL.

[0046] The preferred ratio of the amounts of iron salt, 2-aminoterephthalic acid, and solvent in the solution is 6 mmol: 3 mmol: 60 mL.

[0047] The molar ratio of Ti in MIL-125-NH2 and Fe in MIL-101-NH2 in the MIL-101-NH2 complex is selected as 1-5:1-5.

[0048] The preferred molar ratio of Ti in MIL-125-NH2 and Fe in MIL-101-NH2 in the MIL-101-NH2 complex is 1-2:2-3.

[0049] The molar ratio of Ti in MIL-125-NH2 and Fe in MIL-101-NH2 in the MIL-101-NH2 complex is further preferably 1:3.

[0050] The homogeneous reaction conditions are selected from: temperature 130-90℃; heating rate 5-15℃ / min; reaction time 22-18 hours.

[0051] The preferred homogeneous reaction conditions are: temperature 120-100℃; heating rate 5-10℃ / min; reaction time 22-19 hours.

[0052] The preferred homogeneous reaction conditions are: temperature 110℃; heating rate 5℃ / min; reaction time 20 hours.

[0053] The loading method in step (3) is as follows: the MIL-101-NH2 complex prepared in step (2) is mixed and reacted with a solution containing zinc salt, indium salt and thioacetamide. The precipitate after the reaction is washed and dried to obtain the MOF-based material.

[0054] The zinc salt is preferably at least one of zinc chloride, zinc acetate dihydrate, and zinc nitrate hexahydrate.

[0055] The zinc salt is further preferably at least one of zinc chloride and zinc acetate dihydrate.

[0056] The zinc salt is more preferably zinc chloride.

[0057] The indium salt is preferably at least one of indium trichloride tetrahydrate, indium nitrate, and indium acetylacetonate.

[0058] The indium salt is further preferably at least one of indium trichloride tetrahydrate and indium nitrate.

[0059] The indium salt is more preferably indium trichloride tetrahydrate.

[0060] The solution used in the loading method is selected from at least one of glycerol, deionized water, ethylene glycol and DMF.

[0061] The solution used in the loading method is preferably at least one of glycerol, deionized water, ethylene glycol, and DMF.

[0062] The solution used in the loading method is further preferably at least one of glycerol, deionized water, and ethylene glycol.

[0063] The solution used in the loading method is more preferably a combination of glycerol and deionized water.

[0064] The preferred volume ratio of glycerol to deionized water is 1:2-6; more preferably 1:4-5; and even more preferably 1:4.

[0065] The pH of the solution in the loading method is selected from 1.5-9.5.

[0066] The pH of the solution in the loading method is preferably 2-5.5.

[0067] The pH of the solution in the loading method is further preferably 2.5.

[0068] The loading method uses zinc salt, indium salt, thioacetamide and solvent in a solution with the following ratios: 0.102-0.510g: 0.331-1.655g: 0.15-0.75g: 40-200mL.

[0069] The preferred ratio of the amounts of zinc salt, indium salt, thioacetamide, and solvent in the solution during the loading method is: 0.102-0.306g: 0.331-0.993g: 0.15-0.45g: 40-120mL.

[0070] The preferred ratio of the amounts of zinc salt, indium salt, thioacetamide, and solvent in the solution during the loading method is: 0.102 g : 0.331 g : 0.15 g : 40 mL.

[0071] The amount of MIL-101-NH2 complex added to the MOF-based material is selected from 20-70 mg.

[0072] The preferred amount of MIL-101-NH2 complex added to the MOF-based material is 30-60 mg.

[0073] The preferred amount of the MIL-101-NH2 complex added to the MOF-based material is 30 mg.

[0074] The reaction conditions for the load are selected from: temperature 100-60℃; reaction time 100-140 minutes.

[0075] The preferred reaction conditions for the load are: temperature 90-70℃; reaction time 110-130 minutes.

[0076] The reaction conditions for the load are further preferably: temperature 80°C, reaction time 120 minutes.

[0077] Based on further solutions to the technical problems of the present invention, or simultaneous solutions to multiple technical problems, the preferred solution in the technical solution provided in the first aspect of the present invention includes: The first preferred embodiment is a method for preparing MOF-based materials, which involves composite MIL-101-NH2 onto MIL-125-NH2 to obtain a MIL-101-NH2 composite, and then loading an indium catalyst onto the MIL-101-NH2 composite to obtain the MOF-based material. This technical solution not only solves the technical problem of "inability to simultaneously remove heavy metal ions and organic pollutants," but also further addresses the technical problem of "poor recyclability of existing MOF composite photocatalytic materials."

[0078] The second preferred embodiment is a method for preparing MOF-based materials, which involves supporting a MIL-101-NH2 composite containing a specific mass ratio of MIL-125-NH2 and MIL-101-NH2 with an indium catalyst to obtain the MOF-based material. This technical solution, while addressing the existing problems of "poor recyclability of MOF-based materials and inability to simultaneously remove heavy metal ions and organic pollutants," further solves the problem of "recyclability of MOF-based materials."

[0079] The third preferred option is a method for preparing MOF-based materials, which involves loading a specific indium catalyst onto a MIL-101-NH2 composite to obtain MOF-based materials. This technical solution not only solves the technical problem of "poor recyclability of existing MOF composite photocatalytic materials and inability to simultaneously remove heavy metal ions and organic pollutants", but also further solves the technical problem of "improving the simultaneous removal efficiency of heavy metal ions and organic pollutants".

[0080] The fourth preferred embodiment is a method for preparing MOF-based materials, wherein an indium catalyst is supported on a MIL-101-NH2 composite to obtain a MOF-based material containing a specific ratio of the MIL-101-NH2 composite and the indium catalyst. This technical solution, while addressing the existing technical problem of "poor recyclability of MOF composite photocatalytic materials and inability to simultaneously remove heavy metal ions and organic pollutants," further solves the technical problem of "improving the simultaneous removal efficiency of heavy metal ions and organic pollutants."

[0081] The fifth preferred option is a method for preparing MOF-based materials, wherein an indium catalyst is supported on a MIL-101-NH2 composite under specific reaction conditions to obtain MOF-based materials. This technical solution not only solves the technical problem of "poor recyclability of existing MOF-based materials and inability to simultaneously remove heavy metal ions and organic pollutants", but also further solves the technical problem of "improving the efficiency of simultaneous removal of heavy metal ions and organic pollutants".

[0082] Secondly, the present invention provides: a MOF-based material prepared by the above-described preparation method.

[0083] Among its technical features is MOF-based materials.

[0084] Thirdly, the present invention provides the application of the MOF-based material in the removal of pollutants from water.

[0085] This includes technical characteristics: pollutants and applications.

[0086] The contaminant is preferably at least one of hexavalent chromium ions and antibiotics.

[0087] Preferably, the hexavalent chromium ion is derived from at least one of dichromate ion, chromate ion and hydrogen chromate ion; Further preferred are those derived from dichromate ions and chromate ions; even more preferred are those derived from dichromate ions.

[0088] Preferably, the antibiotic is at least one of ciprofloxacin, tetracycline, and ofloxacin; More preferably, at least one of ciprofloxacin and ofloxacin; Ciprofloxacin is preferred.

[0089] Fourthly, the present invention provides a method for removing hexavalent chromium ions and antibiotics from water, comprising the steps of mixing the above-mentioned MOF-based material with water to carry out a photocatalytic reaction.

[0090] Among its technical features are: mixing and photocatalytic reaction.

[0091] The water body is preferably composed of at least one of hexavalent chromium ions and antibiotics.

[0092] Preferably, the hexavalent chromium ion is derived from at least one of dichromate ion, chromate ion and hydrogen chromate ion; Further preferred are those derived from dichromate ions and chromate ions; Even more preferably, it is derived from dichromate ions.

[0093] Preferably, the antibiotic is at least one of ciprofloxacin, tetracycline, and ofloxacin; More preferably, at least one of ciprofloxacin and ofloxacin; Ciprofloxacin is preferred.

[0094] The pH of the water is preferably 1.5-9.5; more preferably 3.5-5.5; and even more preferably 3.5.

[0095] The MOF-based material is preferably added at a ratio of 3-9 times the total amount of hexavalent chromium ions and antibiotics; more preferably 5-7 times; and even more preferably 6 times.

[0096] The preferred conditions for the photocatalytic reaction are 20-60 min of light irradiation at a temperature of 20-50°C; more preferably, 30-40 min of light irradiation at a temperature of 20-30°C; and even more preferably, 30 min of light irradiation at a temperature of 25°C.

[0097] In this invention, embodiments 1-5 at least support the protection scope of "composite" and "load".

[0098] The term "composite" is derived from the aforementioned explanation and / or the corresponding technical features in Examples 1-5, such as "MIL-125-NH2 prepared in step (1) is mixed with a solution containing iron salt, 2-aminoterephthalic acid, and N,N-dimethylformamide for a homogeneous reaction, and the precipitate is washed and dried to obtain the MIL-101-NH2 complex," and is summarized by the common feature "a material design and preparation strategy that combines two or more basic units with different compositions, structures, or functions into one through physical doping, chemical bonding, interface assembly, etc., to achieve synergistic effects between the basic units, thereby improving the performance defects of single photocatalytic materials in terms of light absorption, charge separation, and catalytic activity." Therefore, those skilled in the art can reasonably presume that "composite," its subordinate concepts, its essentially equivalent technical means, and technical means that can replace it within the scope of conventional technical means and common knowledge based on the existing technical level should all fall within the protection scope of "composite."

[0099] The term "load" is derived from the aforementioned explanation and / or the corresponding technical features in Examples 1-5, such as "the method of loading is: the MIL-101-NH2 composite prepared in step (2) is mixed and reacted with a solution containing zinc salt, indium salt and thioacetamide, and the precipitate after the reaction is washed and dried to obtain the MOF-based material," and is further summarized by the common feature "a material modification process in which one or more active components with specific functions (such as metal nanoparticles, co-catalysts, quantum dots, etc.) are fixed on the surface or pores of a carrier material (such as semiconductor matrix, carbon material, molecular sieve, etc.) with a high specific surface area and stable structure through physical adsorption, chemical deposition, chemical bonding, in-situ growth, etc.; the purpose of which is to improve the dispersibility and utilization rate of the active components, enhance the interfacial interaction between the active components and the carrier, and thus improve the photocatalytic performance of the composite material." Therefore, those skilled in the art can reasonably presume that "load," its subordinate concepts, its basically equivalent technical means, and technical means that can replace it within the scope of conventional technical means and common knowledge based on the existing technical level should all fall within the protection scope of "load."

[0100] Examples 1-5 of this invention at least support the scope of protection for "application in removing pollutants from water bodies".

[0101] The term "application in removing pollutants from water bodies" is summarized from the foregoing explanation and / or the corresponding technical features in Examples 1-5, such as "the pollutant is preferably at least one of hexavalent chromium ions and antibiotics." Therefore, those skilled in the art can reasonably infer that "application in removing pollutants from water bodies," its subordinate concepts, its substantially equivalent technical means, and technical means that can replace it within the scope of conventional and common knowledge based on the existing level of technology should all fall within the protection scope of this invention.

[0102] Examples 1-5 of this invention at least support the protection scope of "photocatalytic reaction".

[0103] "Photocatalytic reaction" is summarized by the aforementioned explanation and / or the corresponding technical features in Examples 1-5, such as "the amount of MOF-based material added is preferably 3-9 times the total amount of hexavalent chromium ions and antibiotics" and "the conditions for the photocatalytic reaction are preferably 20-60 min of light irradiation and 20-50℃". It is further summarized by the common feature that "using light as the energy input source, a series of redox reactions are initiated under the catalytic action of the photocatalytic material; specifically, after the photocatalytic material absorbs photon energy equal to or greater than its band gap, valence band electrons are excited and jump to the conduction band, forming photogenerated electron-hole pairs. These charge carriers migrate to the material surface and undergo redox reactions with adsorbed reactants (such as organic pollutants, water molecules, oxygen, etc.) to achieve the target processes of pollutant degradation, hydrogen production, and carbon dioxide reduction; this reaction is usually carried out at room temperature and pressure, and has the characteristics of low energy consumption and environmental friendliness". Therefore, based on reasonable presumption, those skilled in the art can determine that "photocatalytic reaction", its subordinate concepts, its essentially equivalent technical means, and technical means that can replace it within the scope of conventional technical means and common knowledge based on the current level of technology should all fall within the protection scope of "photocatalytic reaction".

[0104] The beneficial effects of this invention are as follows: The present invention has at least the following beneficial effects: 1. Compared with the prior art, the present invention has better technical effects in improving the recyclability of MOF-based materials and simultaneously removing hexavalent chromium ions and antibiotics.

[0105] According to experimental tests, this invention increases the recyclability of MOF-based materials from 4 cycles in the prior art to more than 8 cycles.

[0106] According to experimental tests, this invention achieves the simultaneous removal of hexavalent chromium ions and antibiotics, with a removal rate of 100% for both hexavalent chromium ions and antibiotics.

[0107] Furthermore, based on the present invention: 1. Based on the comparison of Examples 1-5 and Comparative Examples 3-4, the present invention adopts the technical means of "MIL-125-NH2 composite with MIL-101-NH 2、 The combination of methods such as "MIL-125-NH2 preparation" has achieved new technical results, "significantly improving Cr 6+ "And CIP removal efficiency." The combined technical effect is superior to the sum of the effects of each individual technique.

[0108] 2. Based on the comparison of Examples 1-5 and Comparative Examples 2-3, the present invention purposefully selected a narrower range not mentioned in the prior art from the broad scope disclosed in the prior art: "the molar ratio of Ti in MIL-125-NH2 and Fe in MIL-101-NH2 in the MIL-101-NH2 complex is selected from 1-5:1-5", achieving an unexpected technical effect: "significantly improving Cr 6+ "and CIP removal efficiency", etc. Attached Figure Description

[0109] Figure 1 The images shown are SEM images of the present invention. In the images, A is a scanning electron microscope image of MIL-101-NH2; B is a scanning electron microscope image of MIL-125-NH2; C is a scanning electron microscope image of ZnIn2S4; and D is a scanning electron microscope image of MOF-based material (ZIS@Fe / Ti-MOF).

[0110] Figure 2 This is the XRD pattern of the MOF-based material (ZIS@Fe / Ti-MOF) of this invention.

[0111] Figure 3 This is the FTIR image of the MOF-based material (ZIS@Fe / Ti-MOF) of this invention.

[0112] Figure 4 This is a diagram showing the pollutant degradation of the MOF-based material (ZIS@Fe / Ti-MOF) of this invention and its degradation efficiency at 3% salinity.

[0113] Figure 5 The MOF-based material (ZIS@Fe / Ti-MOF) of this invention is effective against Cr. 6+ Kinetic fitting plot with CIP degradation. Detailed Implementation

[0114] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0115] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0116] Example 1: A MOF-based material (ZIS@Fe / Ti-MOF) and its preparation method The preparation method includes the following steps: (1) Place 0.6 mL of tetrabutyl titanate and 0.56 g of NH2-H2BDC in a beaker containing 36 mL of DMF and 4 mL of methanol; stir until the solution is uniform and then place it in a homogeneous reactor and react at 150 °C for 24 h; after the reaction is complete, wash with DMF and methanol 3 times each and centrifuge, place in a vacuum drying oven at 60 °C for 12 h, and recover the powder sample as MIL-125-NH2.

[0117] (2) Place 6 mmol FeCl3·6H2O and 3 mmol NH2-H2BDC in a beaker containing 60 mL DMF; add the powder sample obtained in step (1) to the beaker, stir until the solution is uniform, and then place it in a homogeneous reactor and react at 110 °C for 20 h; after the reaction is complete, wash with DMF and ethanol 3 times each, centrifuge, and place in a vacuum drying oven at 60 °C for 12 h. The recovered powder sample is MIL-125-NH2-MIL-101-NH2 (the molar ratio of Ti (2 mmol) in MIL-125-NH2 to Fe (6 mmol) in MIL-101-NH2 is 1:3).

[0118] (3) Place 0.102g ZnCl2, 0.331g InCl3·4H2O and 0.15g thioacetamide in a beaker containing 8mL glycerol and 32mL deionized water with pH=2.5; stir until clear, then add 30mg of Fe / Ti-MOF powder sample obtained in step (2), stir until the solution is uniform, place in an oil bath, and react in an oil bath at 80℃ for 2h. After the reaction is complete, wash twice with ethanol and centrifuge, then place in a vacuum drying oven at 60℃ for 12h. The recovered powder sample is MOF-based material (ZIS@Fe / Ti-MOF).

[0119] Example 2 The only difference from Example 1 is that in step (2), the ratio of MIL-125-NH2 to MIL-101-NH2 is 1:1 (the molar ratio of Ti in MIL-125-NH2 to Fe in MIL-101-NH2 is 1:1; both are 2 mmol); the other steps are the same as in Example 1.

[0120] Example 3 The only difference from Example 1 is that in step (2), the ratio of MIL-125-NH2:MIL-101-NH2 is 1:2 (the molar ratio of Ti (2 mmol) in MIL-125-NH2 to Fe (4 mmol) in MIL-101-NH2 is 1:2); the other steps are the same as in Example 1.

[0121] Example 4 The only difference from Example 1 is that 45 mg of Fe / Ti-MOF powder sample is added in step (3); the other steps are the same as in Example 1.

[0122] Example 5 The only difference from Example 1 is that 60 mg of Fe / Ti-MOF powder sample is added in step (3); the other steps are the same as in Example 1.

[0123] Comparative Example 1 The only difference from Example 1 is that MIL-101(Al)-NH2 is compounded on MIL-125-NH2.

[0124] Comparative Example 2 The only difference from Example 1 is that the molar ratio of Ti in MIL-125-NH2 and Fe in MIL-101-NH2 in the MIL-101-NH2 complex is 8:1.

[0125] Comparative Example 3 The only difference from Example 1 is that the molar ratio of Ti in MIL-125-NH2 and Fe in MIL-101-NH2 in the MIL-101-NH2 complex is 1:8.

[0126] Comparative Example 4 The only difference from Example 1 is that the step of combining MIL-125-NH2 with MIL-101-NH2 is omitted.

[0127] Comparative Example 5 The only difference from Example 1 is that the step of preparing MIL-125-NH2 is omitted.

[0128] Comparative Example 6 The only difference from Example 1 is that the catalyst supported on the MIL-101-NH2 complex is g-C3N4.

[0129] Comparative Example 7 The only difference from Example 1 is that the amount of MIL-101-NH2 complex added to the MOF-based material is 20 mg.

[0130] Comparative Example 8 The only difference from Example 1 is the reaction temperature during the loading process. Specifically, the oil bath reaction temperature is 70°C; all other steps are the same as in Example 1.

[0131] Detection example The structures of the MOF-based material (ZIS@Fe / Ti-MOF) and its intermediate products prepared in Example 1 were characterized as follows: 1. Scanning electron microscopy (SEM) analysis: Figure 1 Image A is a scanning electron microscope image of MIL-101-NH2, which shows that its morphological characteristics are smooth octahedral shapes. Figure 1 Image B is a scanning electron microscope image of MIL-125-NH2, which shows that its morphology is a uniform and regular nano-cake shape. Figure 1 C in the image is a scanning electron microscope image of ZnIn2S4, which shows that its morphology is characterized by a layered nanosphere shape. Figure 1 In the image, D is a scanning electron microscope image of the MOF-based material (ZIS@Fe / Ti-MOF). It can be observed that the spindle-shaped surface of MIL-101-NH2 becomes rough, indicating that MIL-125-NH2 and ZnIn2S4 were successfully loaded on the surface of MIL-101-NH2, proving that the MOF-based material ZIS&MIL-125-NH2-MIL-101-NH2 (abbreviated as ZIS@Fe / Ti-MOF) was successfully prepared.

[0132] 2. X-ray diffraction analysis (XRD): By observing and comparing the X-ray diffraction spectra of the prepared MOF-based materials, it was found that the diffraction peaks of the MOF-based materials were consistent with those of ZIS. The strong absorption peaks formed by ZIS on the surface of MIL-125-NH2-MIL-101-NH2 led to a decrease in the intensity of the diffraction peaks of MIL-125-NH2 and MIL-101-NH2.

[0133] 3. Fourier Transform Infrared Spectroscopy (FTIR): The Fourier transform infrared (FTIR) spectra of the prepared MOF-based material (ZIS@Fe / Ti-MOF) revealed that the MOF-based material (ZIS@Fe / Ti-MOF) exhibited performance in the range of 3000-3661 cm⁻¹. -1 The broad peaks are mainly caused by the symmetric stretching vibrations of the amino groups in MIL-125-NH2 and MIL-101-NH2. The peaks at 1434 and 1656 cm⁻¹ are... -1 The strong bands in the region are due to the presence of symmetric and asymmetric stretching vibrations of the OCO in MIL-125-NH2 and MIL-101-NH2. Furthermore, FO vibrations occur at 517 cm⁻¹. -1 This is a typical characteristic peak of MIL-101-NH2.

[0134] 4. Degradation efficiency of pollutants: This study used 50 ppm Cr 6+ Using 50 ppm CIP as the target pollutant and 30 mg of the composite material as the test material, the adsorption and photocatalytic performance of the composite material was evaluated. The test procedure is as follows: Prepare an initial concentration of 50 mg / L of CIP... 6+CIP simulated wastewater was prepared by adding 0.03 g of the prepared MOF-based material (ZIS@Fe / Ti-MOF) photocatalyst to 50 mL of simulated wastewater. The reaction was carried out under constant temperature shaking at 25℃, 200 rpm, and visible light irradiation. At regular intervals, 3 mL of the solution was collected, filtered through a 0.22 μm filter membrane, and the supernatant was used to determine the residual concentration of CIP using high-performance liquid chromatography (HPLC). Cr was determined using ICP-OES and a visible-ultraviolet spectrophotometer. 6+ The remaining concentration was used to calculate the degradation efficiency. After the reaction, the material was washed with ethanol, vacuum dried, and then reused in photocatalytic degradation experiments to test the reusability of the material.

[0135] Test results are as follows Figure 4 As shown, after 30 minutes of reaction, Cr 6+ The degradation efficiency with CIP reached approximately 100%; after five cycles of catalyst recycling, the degradation efficiency remained above 87%, indicating excellent catalytic degradation activity and cycle stability. NaCl solution was used as the salinity test salt. The figures show the effects of the composite material on Cr under 3% salinity. 6+ The degradation efficiency of CIP and the composite material can be observed. 6+ The degradation rate of CIP decreased somewhat, but fortunately, the impact was not significant. Although the time to complete degradation was delayed from 30 minutes in salinity-free conditions to 60 minutes, heavy metals and organic matter were still degraded to about 90% after 30 minutes, and completely degraded at around 60 minutes. The reason why the adsorption and photocatalytic performance of the composite material is affected by salinity may be due to the presence of Cl during the photocatalytic process. - It can affect the generation of active substances such as ·OH, further impacting photocatalytic performance.

[0136] 5. This invention relates to Cr 6+ Kinetic fit with CIP degradation: like Figure 5 As shown, the prepared MOF-based material has a material effect on Cr 6+ The degradation rate of CIP is very fast, and its kinetic fitting model shows that it conforms to first-order kinetics.

[0137] Effect test: Each embodiment and comparative example selected Cr 6+ Using ciprofloxacin (CIP) as a model pollutant, the photocatalytic performance of MOF-based material (ZIS@Fe / Ti-MOF) was tested. The specific steps were as follows: 50 mg / L Cr... 6+50 mL of a 50 mg / L CIP solution was prepared, with a pH of 3.5. 30 mg of MOF-based material (ZIS@Fe / Ti-MOF) was added to each solution. The experiment was first performed in the dark for 30 min in a digital display water bath constant temperature shaker, followed by 30 min of photochemical reaction under light. After the reaction, 3 mL of each solution was filtered through a 0.22 μm filter membrane for ICP-OES detection of Cr. 6+ The concentration of CIP was determined by HPLC using 1.5 mL of the solution filtered through a 0.22 μm membrane. The specific results are shown in the table below. Table 1. Photocatalytic performance results

[0138] Verification of technical effectiveness and / or analysis of technical problem solving As can be seen from Examples 1-6, the MOF-based material (ZIS@Fe / Ti-MOF) obtained by the preparation method of Example 1 has good Cr content. 6+ CIP has the highest removal efficiency.

[0139] As shown in Comparative Examples 1-7, the optimal combination for preparing MOF-based materials (ZIS@Fe / Ti-MOF) is MIL-125-NH2(Ti), MIL-101-NH2(Fe), and ZnIn2S4.

[0140] As shown in Comparative Example 8, the optimal conditions for preparing MOF-based materials (ZIS@Fe / Ti-MOF) are an oil bath temperature of 80℃.

[0141] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing MOF-based materials, characterized in that, Includes the following steps: (1) Preparation of MIL-125-NH2; (2) MIL-101-NH2 is compounded onto MIL-125-NH2 in step (1) to obtain the MOF complex; (3) The MOF composite prepared in step (2) is loaded with indium catalyst to obtain the MOF-based material.

2. The preparation method according to claim 1, characterized in that, The preparation method of MIL-125-NH2 in step (1) is as follows: titanium compound and 2-aminoterephthalic acid are subjected to homogeneous reaction in an organic solvent. After the reaction, the precipitate is washed and dried to obtain MIL-125-NH2.

3. The preparation method according to claim 2, characterized in that, The titanium compound is at least one of tetrabutyl titanate, titanium tetrachloride, titanium oxysulfate, and tetraethyl titanate; preferably at least one of tetrabutyl titanate and tetraethyl titanate; more preferably tetrabutyl titanate. The organic solvent is selected from at least one of DMF, MeOH, EtOH, H2O and 1,4-dioxane; preferably at least one of DMF, MeOH, EtOH and 1,4-dioxane; more preferably at least one of DMF, MeOH and EtOH; and even more preferably a combination of DMF and MeOH. The volume ratio of DMF to MeOH in the organic solvent is 12:1-6:1; preferably 10:1-8:1; more preferably 9:

1. The titanium compound, 2-aminoterephthalic acid, and organic solvent are selected from the following ratios: 0.9-0.4 mL : 0.78-0.34 g : 60-20 mL; preferably: 0.7-0.5 mL : 0.67-0.45 g : 50-30 mL; and more preferably: 0.6 mL : 0.56 g : 40 mL. The conditions for the homogeneous reaction are selected from: temperature 170-130℃; heating rate 5-15℃ / min; reaction time 26-22 hours; preferably: temperature 160-140℃; heating rate 5-10℃ / min; reaction time 26-23 hours; more preferably: temperature 150℃; heating rate 5℃ / min; reaction time 24 hours.

4. The preparation method according to claim 1, characterized in that, The composite method described in step (2) is as follows: MIL-125-NH2 prepared in step (1) is mixed with a solution containing iron salt, 2-aminoterephthalic acid and N,N-dimethylformamide for homogeneous reaction. After the reaction, the precipitate is washed and dried to obtain the MIL-101-NH2 complex.

5. The preparation method according to claim 4, characterized in that, The iron salt is at least one of ferric chloride hexahydrate, ferric nitrate nonahydrate, and ferric sulfate; preferably at least one of ferric chloride hexahydrate and ferric nitrate nonahydrate; more preferably ferric chloride hexahydrate. The solvent of the solution is selected from at least one of DMF, methanol, ethanol and water; preferably at least one of DMF, methanol, ethanol and water; more preferably at least one of DMF, methanol and ethanol; and even more preferably at least one of DMF. The ratio of the amount of iron salt, 2-aminoterephthalic acid, and solvent in the solution is selected from: 8-2 mmol: 5.5-0.5 mmol: 70-40 mL; preferably: 6-4 mmol: 3.5-2 mmol: 60-50 mL; and more preferably: 6 mmol: 3 mmol: 60 mL. The molar ratio of Ti in MIL-125-NH2 and Fe in MIL-101-NH2 in the MIL-101-NH2 complex is selected from: 1-5:1-5; preferably: 1-2:2-3; more preferably: 1:3; The homogeneous reaction conditions are selected from: temperature 130-90℃; heating rate 5-15℃ / min; reaction time 22-18 hours; preferably: temperature 120-100℃; heating rate 5-10℃ / min; reaction time 22-19 hours; more preferably: temperature 110℃; heating rate 5℃ / min; reaction time 20 hours.

6. The preparation method according to claim 1, characterized in that, The loading method in step (3) is as follows: the MIL-101-NH2 complex prepared in step (2) is mixed and reacted with a solution containing zinc salt, indium salt and thioacetamide. The precipitate after the reaction is washed and dried to obtain the MOF-based material.

7. The preparation method according to claim 6, characterized in that, The zinc salt is at least one of zinc chloride, zinc acetate dihydrate, and zinc nitrate hexahydrate; preferably at least one of zinc chloride and zinc acetate dihydrate; more preferably zinc chloride. The indium salt is selected from at least one of indium trichloride tetrahydrate, indium nitrate, and indium acetylacetonate; preferably, it is at least one of indium trichloride tetrahydrate and indium nitrate; more preferably, it is indium trichloride tetrahydrate. The solution is selected from at least one of glycerol, deionized water, ethylene glycol, and DMF; preferably at least one of glycerol, deionized water, ethylene glycol, and DMF; more preferably at least one of glycerol, deionized water, and ethylene glycol; and even more preferably a combination of glycerol and deionized water. The preferred volume ratio of glycerol to deionized water is 1:2-6; more preferably 1:4-5; and even more preferably 1:

4. The pH of the solution is selected from: 1.5-9.5; preferably: 2-5.5; more preferably: 2.5; The ratio of zinc salt, indium salt, thioacetamide, and solvent in the solution is selected from: 0.102-0.510g : 0.331-1.655g : 0.15-0.75g : 40-200mL; preferably: 0.102-0.306g : 0.331-0.993g : 0.15-0.45g : 40-120mL; more preferably: 0.102g : 0.331g : 0.15g : 40mL; The amount of MIL-101-NH2 complex added to the MOF-based material is selected from: 20-70 mg; preferably 30-60 mg; more preferably 30 mg; The reaction conditions for the load are selected from: temperature 100-60℃; reaction time 100-140 minutes; preferably: temperature 90-70℃; reaction time 110-130 minutes; more preferably: temperature 80℃; reaction time 120 minutes.

8. A MOF-based material prepared by the preparation method according to any one of claims 1-7.

9. The application of the MOF-based material according to claim 8 in the removal of pollutants from water.

10. A method for removing hexavalent chromium ions and antibiotics from water, characterized in that, The process includes the step of mixing the MOF-based material of claim 8 with water to carry out a photocatalytic reaction.

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