Modified MIL-101 is used for the adsorption and removal of tetracycline antibiotics in water systems.

Abstract

Modified MIL-101 is used for the adsorption and removal of tetracycline antibiotics from water systems, a field recognized in the water treatment field. A new application of the material MIL-101-X, where X represents a fatty amine, is for the adsorption and removal of tetracycline antibiotics from water systems. The principle is that the effective pore size of the modified MIL-101, particularly MIL-101-dod, is comparable to the molecular size of tetracycline antibiotics. Furthermore, the amino groups in the MIL-101-dod material, pointing inward toward the pores, attract the hydroxyl groups on the outside of the antibiotic molecules to form hydrogen bonds. This allows for excellent static adsorption of tetracycline antibiotics from aqueous solutions within the pores of the material. This material is simple to prepare, exhibits strong stability, exhibits significant adsorption of tetracycline antibiotics in water, and has good potential for recycling.

Description

Technical Field

[0001] This invention relates to the field of metal-organic framework technology, and to the application of a novel modified MIL-101 material, which has a microporous structure and can adsorb and remove tetracycline antibiotics from aqueous systems. Background Art

[0002] Tetracycline antibiotics, including tetracycline, oxytetracycline, chlortetracycline, and methacycline, are a class of widely used broad-spectrum antibiotics. They primarily work by inhibiting protein synthesis in bacteria, playing a vital role in clinical medicine and livestock farming. However, the overuse of tetracycline and other antibiotics has led to severe pollution of soil and water bodies, and even the emergence of various drug-resistant bacteria, posing a serious threat to the ecological environment and human health.

[0003] Generally, antibiotics in water are treated through photodegradation, biodegradation, hydrolysis, and adsorption. Among these, adsorption has attracted widespread attention due to its significant advantages such as simple operation and low energy consumption. Because tetracycline antibiotics exist at relatively low concentrations in the environment, current traditional adsorbents have limited removal capabilities. Therefore, developing adsorbents with high adsorption capacity and strong limiting adsorption ability for tetracyclines is particularly important.

[0004] Metal-organic frameworks (MOFs) are novel porous materials with high porosity and high specific surface area, formed by the complexation of metal ions or metal clusters and organic ligands. Due to the designable structure, easily modifiable and tunable pores, and large specific surface area of ​​porous MOFs, it is relatively easy to design and prepare MOF materials with high adsorption capacity and trace adsorption capability. Their application in the adsorption and removal of environmental pollutants such as heavy metal ions, persistent organic pollutants, pesticides, and veterinary drugs has developed rapidly.

[0005] Tetracycline antibiotics share a common parent nucleus—hydrogenated tetraphenylene. Based on this structural characteristic, MIL-101(Cr), which has a bare metal site and a large specific surface area, was selected and post-synthesized with dodecylamine (DOD) to enhance the interaction between the MOF framework and tetracycline. The adsorption and removal effect of MIL-101 on tetracycline antibiotics was then investigated. Summary of the Invention

[0006] The purpose of this invention is to use a series of MIL-101 materials with different alkyl chain modifications for adsorbing tetracycline antibiotics, so as to solve the problem of selective removal of tetracycline antibiotics in aqueous systems.

[0007] To achieve the above objectives, the present invention provides a series of new uses for MIL-101-X materials synthesized by improved hydrothermal method, where X = aliphatic amine, preferably pro, hex, dod, or oct, wherein pro is propylamine (Propylamine = Pro), hex is n-hexylamine (n-Hexylamine = Hex), dod is n-Dodecylamine (n-Dodecylamine = Dod), and oct is octadecanamine (Octadecanamine = Octt), with dod being more preferred.

[0008] This invention uses the MIL-101-X series of materials for adsorption and removal of tetracycline antibiotics in water systems, for static adsorption or packed filter-type breakthrough adsorption. The tetracycline antibiotics are one or more of tetracycline, doxycycline, oxytetracycline, chlortetracycline hydrochloride, etc.

[0009] Static adsorption and breakthrough experiments demonstrate that the MIL-101-X series material exhibits excellent adsorption performance of tetracycline antibiotics in water. 1–10 mg of this material can statically or through breakthrough adsorb 40–90 mL of mixed tetracycline solutions with concentrations at the ppm level, demonstrating its significant application value in trace adsorption of tetracycline antibiotics. The treatment temperature range is wide, from room temperature to 50℃.

[0010] The principle behind this method is that the effective pore size of modified MIL-101, especially MIL-101-dod, is comparable to the molecular size of tetracycline antibiotics. Furthermore, the amino groups pointing inwards in the pores of MIL-101-dod can attract the hydroxyl groups on the outside of the antibiotic molecule to form hydrogen bonds. Therefore, static adsorption of tetracycline antibiotics in aqueous solution can be effectively achieved within the pores of this material. The preparation process of this material is simple, it has strong stability, exhibits significant adsorption effects on tetracycline antibiotics in water, and possesses good potential for recycling. Attached Figure Description

[0011] Figure 1 The UV spectrum of 1 mg MIL-101-X material after static adsorption experiment on 4 mL of tetracycline, doxycycline, oxytetracycline and chlortetracycline hydrochloride aqueous solution with an initial concentration of 5 ppm at room temperature.

[0012] Figure 2 This is a schematic diagram of the effluent concentration from a breakthrough experiment of 5 mg MIL-101-dod material at room temperature for a tetracycline solution with an initial concentration of 5 ppm; it can be seen that the tetracycline solution with a concentration higher than 60 ml was completely adsorbed.

[0013] Figure 3This is a schematic diagram of the effluent concentration in the breakthrough experiment of a mixed solution of five tetracycline antibiotics (tetracycline, doxycycline, oxytetracycline, methacycline hydrochloride, and chlortetracycline hydrochloride, each with a concentration of 1 ppm) with an initial concentration of 5 mg MIL-101-dod material at room temperature. Detailed Implementation

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0015] Regarding the improved hydrothermal synthesis of MIL-101-X material, the modifier used is the corresponding aliphatic amine compound. See ZL202110556561X.

[0016] Preferably, the mass ratio of MIL-101 to the modifier is 1:1 to 1:2, and generally the modifier is in excess.

[0017] The specific chemical formulas for the reaction are as follows:

[0018]

[0019] The method for synthesizing and modifying the above-mentioned modified MIL-101 material of the present invention mainly includes the following steps:

[0020] (1) Activation material: MIL-101 is preheated in an oven at 150°C to remove water molecules from the central metal site to obtain activated MIL-101;

[0021] (2) Preparation of primary amine-modified metal site modified MIL-101(Cr)-X: Mix X (X = pro, hex, dod, oct) with proton organic solvent and add it into the reactor. Vacuum and nitrogen protection are applied. Then add the MIL-101(Cr) activated by baking at 150℃ in step (1). Vacuum and nitrogen protection are applied again. Heat to 80-120℃ and reflux for 16-20 hours.

[0022] (3) Purification: After step (2) is completed, impurities are washed away by N,N-dimethylformamide (DMF), ethyl acetate (EA) and petroleum ether (PE) in sequence. The product is purified by centrifugation at 8000 rpm and dried in an oven at 80-120℃ to obtain successfully modified MIL-101-X.

[0023] Preferably, the solvent is an aprotic organic solvent.

[0024] Preferably, the aprotic organic solvent is one or more of cyclohexane or toluene.

[0025] Example 1: Static adsorption of tetracycline

[0026] Step 1: Weigh the milligram level MIL-101-X sample and add it to a glass bottle containing a fixed volume of tetracycline, doxycycline, oxytetracycline, and chlortetracycline hydrochloride aqueous solution at a fixed concentration of ppm. Shake well and let stand for 2 hours.

[0027] Step 2: After centrifuging the above mixture, use a glass dropper to collect the supernatant. Repeat three times to remove any residual MOF material from the solution to avoid affecting the UV spectroscopy measurement.

[0028] Step 3: Measure the concentration change of the above solution using an ultraviolet spectrometer, with a scanning wavelength range of 240nm-460nm.

[0029] Figure 1 The UV spectrum is the result of a static adsorption experiment of 1 mg MIL-101-X material on 4 mL of tetracycline, doxycycline, oxytetracycline and chlortetracycline hydrochloride aqueous solution with an initial concentration of 5 ppm at room temperature.

[0030] The above results indicate that all MIL-101-X materials have a certain adsorption effect on tetracyclines. Among them, MIL-101-dod material can completely adsorb and remove mixed tetracyclines within 2 hours, and has good trace static adsorption performance for tetracycline antibiotics. It has good application prospects in the field of adsorption and removal of tetracycline antibiotics in water.

[0031] Example 2: Penetration Adsorption of Tetracycline

[0032] Step 1: Accurately weigh milligram-level MIL-101-X sample, mix it evenly with quartz sand, and then fill it into a quartz tube with a length of 12cm and an inner diameter of 2mm, alternating it with pure quartz sand.

[0033] Step 2: Prepared tetracycline solutions at ppm levels and mixed tetracycline solutions were passed through quartz tubes filled with MIL-101-X samples at a rate of 2–10 mL / 20 min, respectively. The solutions flowed in from the bottom and out from the top of the tube. 4 mL of the filtrate was collected each time, and its concentration was determined using a UV spectrometer (wavelength 240 nm–460 nm, slit width 5 nm).

[0034] Figure 2 This is a schematic diagram of the effluent concentration in a breakthrough experiment of 5 mg MIL-101-dod material at room temperature against a tetracycline solution with an initial concentration of 5 ppm.

[0035] Figure 3This diagram illustrates the effluent concentration from a breakthrough experiment at room temperature for 5 mg of MIL-101-dod material containing five tetracycline antibiotics (a mixed solution of tetracycline, doxycycline, oxytetracycline hydrochloride, and chlortetracycline hydrochloride, each at 1 ppm) with an initial concentration of 5 ppm. The results show that milligram-level MIL-101-dod samples exhibit good adsorption effects on tetracycline antibiotics; approximately 5 mg of MIL-101-dod can purify about 60 mL of a 5 ppm tetracycline antibiotic solution. Furthermore, the tetracycline concentration in the first 60 mL of filtrate is extremely low, almost undetectable by UV spectroscopy; the concentration of tetracycline antibiotics gradually increases only after 60 mL. The experiment demonstrates that MIL-101-dod possesses excellent trace adsorption performance for tetracycline antibiotics.

[0036] The above description is merely a preferred embodiment of the present invention, but the present invention should not be limited to the content disclosed in this embodiment. Therefore, any equivalent or modified versions made without departing from the spirit of the present invention fall within the scope of protection of the present invention.

Claims

1. A novel application of a modified hydrothermal synthesized MIL-101-X material, where X = dod, for the adsorption and removal of tetracycline antibiotics in aqueous systems; dod is n-dodecylamine, used for trace adsorption and removal. The synthesis and modification method of the modified MIL-101 material mainly includes the following steps: (1) Activation material: MIL-101 is preheated in an oven at 150°C to remove water molecules from the central metal site to obtain activated MIL-101; (2) Preparation of primary amine-modified metal site modified MIL-101(Cr)-X: mix dod with proton organic solvent and add it into the reactor. Vacuum and nitrogen protection are applied. Then add MIL-101(Cr) activated by baking at 150°C in step (1). Vacuum and nitrogen protection are applied again. Heat to 80-120°C and reflux for 16-20 hours. (3) Purification: After step (2) is completed, impurities are washed away by N,N-dimethylformamide, ethyl acetate and petroleum ether in sequence. The product is purified by centrifugation at 8000 rpm and dried in an oven at 80-120℃ to obtain successfully modified MIL-101-X. The solvent is an aprotic organic solvent.

2. The use according to claim 1, characterized in that, The tetracycline antibiotics mentioned are one or more of tetracycline, doxycycline, oxytetracycline, and chlortetracycline hydrochloride.

3. The use according to claim 1, characterized in that, Used for static adsorption or packed filter-type permeation adsorption.

4. The use according to claim 1, characterized in that, Each 1~10 mg of MIL-101-X material corresponds to 60~90 mL of a mixed tetracycline solution at the ppm level for static adsorption or packed filter breakthrough adsorption treatment.

5. The use according to claim 1, characterized in that, The processing temperature range is room temperature - 50℃.

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