Preparation method and application of Mn-MOF material suitable for large-scale production

Abstract

The application discloses a preparation method and application of Mn-MOF material suitable for large-scale production, wherein manganese salt is dissolved in solvent A, terephthalic acid is dissolved in solvent B; the two are respectively fed into a reaction container for mixing and heating stirring, after reaction, the Mn-MOF material is obtained through washing and drying; the molar ratio between the manganese salt and the terephthalic acid is (1-1.5):1, the heating stirring temperature is controlled to be 70-90 DEG C, and the reaction time is controlled to be 50-80 min. The Mn-MOF material prepared by the method is used for adsorbing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) in water, has excellent adsorption performance, and can be used for removing Fe(III), Mn(II), Cu(II) and Zn(II). Compared with a traditional hydrothermal method, the preparation method of the application is simple and rapid for synthesizing Mn-MOF under normal pressure, the reaction process is safe and reliable, and is suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of MOF material manufacturing, and specifically relates to a preparation method of a Mn-MOF material and an application of the Mn-MOF material. Background Art

[0002] Mining operations are prone to environmental pollution, with acid mine drainage (AMD) being a prominent issue. ADM Drainage typically contains a variety of metals, including Fe(III), Mn(II), Cu(II), and Zn(II). Excessive metal ions can have profound impacts on human health and the environment. Therefore, developing methods and materials for treating Fe(III), Mn(II), Cu(II), and Zn(II) under acidic conditions is of great significance to both humans and the natural environment.

[0003] Currently, the main methods used to treat Fe(III), Mn(II), Cu(II), and Zn(II) include adsorption, membrane separation, and chemical precipitation. Adsorption offers the advantages of simplicity and wide application. The key to adsorption lies in the design and selection of the adsorbent material. Traditional adsorbents are significantly affected by the pH of the water, limiting their adsorption effectiveness under strongly acidic conditions. In recent years, metal-organic frameworks (MOFs), porous compounds composed of metal ions and organic ligands, have emerged as promising materials for treating Fe(III), Mn(II), Cu(II), and Zn(II) under acidic conditions. These materials possess not only large surface areas and high porosity, but also excellent water and acid-base stability.

[0004] Metal-organic frameworks (MOFs) are porous crystalline materials formed by the self-assembly of metal ions or metal clusters with organic ligands. These materials combine the excellent properties of both inorganic and organic materials, boasting not only a high specific surface area but also excellent water and acid-base stability. They have attracted considerable research interest and, due to their unique advantages, are widely used in fields such as catalysis, gas separation, sensors, and drug delivery. The main methods for synthesizing MOFs include solvothermal, hydrothermal, microwave, and ultrasound-assisted methods.

[0005] Existing methods for synthesizing Mn-MOFs primarily rely on hydrothermal reactors. This method is time-consuming and requires completion in a high-temperature, high-pressure reactor. Furthermore, the pressure inside the vessel cannot be controlled during the reaction, often resulting in poor reproducibility. Therefore, a method for rapidly and stably synthesizing Mn-MOFs at ambient pressure was developed.

[0006] For example, the synthesis method of a rod-shaped MOF74(Mn) assembled by sheets disclosed by Chinese patent CN201911179183.7 comprises dissolving 2,5-dihydroxyterephthalic acid and a 50% manganese nitrate solution in a mixed solution of N,N-dimethylformamide, anhydrous ethanol and deionized water, transferring the mixed solution to a reaction kettle, and heating for a period of time. After the reaction is completed, the sheet-assembled rod-shaped manganese-based MOF is obtained by centrifugal washing and drying. The synthesis method obtains sheet-assembled rod-shaped manganese-based MOF by hydrothermal synthesis method, and the size and morphology of the MOF can be controlled by adjusting the reactant ratio, reaction solvent, reaction temperature and reaction time. The prepared sheet-assembled rod-shaped MOF74(Mn) material can be used as a new catalytic material. The synthesis method is carried out at high temperature and high pressure, and there are problems such as long reaction time, uncontrollable pressure in the container during the reaction, poor repeatability and the like. SUMMARY

[0007] The purpose of the present application is to solve the technical problems of long preparation process time, high reaction temperature, high and uncontrollable reaction pressure, poor repeatability and difficulty in large-scale production of Mn-MOF materials prepared by the existing hydrothermal reaction kettle synthesis method, and the great influence of traditional adsorbents on water pH, and to provide a preparation method of Mn-MOF material which can be carried out at normal pressure, has short reaction time, stable and controllable product quality, and is suitable for large-scale production.

[0008] Another purpose of the present application is to provide the application of the above-mentioned Mn-MOF material.

[0009] To achieve the above-mentioned purpose of the present application, a preparation method of Mn-MOF material suitable for large-scale production comprises the following steps: dissolving manganese salt in solvent A and dissolving terephthalic acid in solvent B; mixing and heating stirring by feeding them into a reaction container respectively, and then washing and drying after reaction to obtain Mn-MOF material; the molar ratio between the manganese salt and terephthalic acid is (1-1.5):1, the heating and stirring temperature is controlled at 70-90°C, and the reaction time is controlled at 50-80 min.

[0010] Preferably, the solvent A is N,N-dimethylformamide.

[0011] Preferably, the solvent B is acetonitrile.

[0012] Preferably, the manganese salt is manganese acetate tetrahydrate.

[0013] Preferably, the molar ratio between the manganese salt and terephthalic acid is (1.3-1.5):1.

[0014] Preferably, the stirring rate is 250-400 rpm.

[0015] Further, the heating stirring temperature is 80℃, the reaction time is 60 min, and the stirring rate is 320 rpm.

[0016] The application of the Mn-MOF material suitable for large-scale production of the application includes: putting the Mn-MOF material into a water body containing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) with pH=1.0-2.0 as an adsorbent for adsorbing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) in the water body.

[0017] Preferably, by detecting the metal ion concentration in the water body containing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II), a certain mass of Mn-MOF is added to the water body containing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) with pH=1.0-2.0 according to the solid-liquid ratio of 1:1 g / L, mixed and reacted for 3 h, and the Mn-MOF loaded with Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) is filtered out.

[0018] Further, the application of the Mn-MOF material suitable for large-scale production of the application is used for treating a solution containing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) with Fe(III) concentration of 0.1-10.4 mg / L, Mn(II) concentration of 0.1-10.6 mg / L, Cu(II) concentration of 0.1-10.3 mg / L, and Zn(II) concentration of 0.1-10.2 mg / L.

[0019] In practical application, the application of the Mn-MOF material suitable for large-scale production of the application specifically includes the following steps:

[0020] (1) A certain mass of Mn-MOF is added to a water solution containing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) with pH=1.0-2.0 according to the solid-liquid ratio of 1:1 g / L, mixed and reacted for 3 h, and the Mn-MOF loaded with Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) is filtered out.

[0021] (2) The Fe(III) concentration of the Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) solution in step (1) is 0.1-10.4 mg / L, the Mn(II) concentration is 0.1-10.6 mg / L, the Cu(II) concentration is 0.1-10.3 mg / L, and the Zn(II) concentration is 0.1-10.2 mg / L.

[0022] (3) After the Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II)-loaded Mn-MOF is filtered out, the concentration of Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) in the water phase is further determined, the amount of Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) adsorbed by the Mn-MOF is obtained by difference, and the adsorption rate (E%) is calculated.

[0023] Compared with the prior art, the preparation method and application of the Mn-MOF material suitable for large-scale production provide a special synthesis reaction environment for metal ions and organic ligands, and provide a new adsorption material for treating Fe(III), Mn(II), Cu(II), and Zn(II) under acidic conditions. The application has the following beneficial effects:

[0024] (1) Compared with the traditional hydrothermal method, the preparation method can control the crystal growth rate by adjusting the stirring rate, and the reaction can be carried out under normal pressure, and the reaction process is safe and reliable.

[0025] (2) The preparation method can control the product grain size and nucleation rate by adjusting the solvent ratio and stirring rate, and can adjust the product form according to market demand.

[0026] (3) The preparation method can quickly synthesize and prepare Mn-MOF at a relatively low temperature of about 80°C, and is suitable for large-scale production.

[0027] (4) The Mn-MOF material prepared by the method has C, Mn, and O elements, has rich oxygen-containing functional groups, provides active sites, has excellent adsorption performance on Fe(III), Mn(II), Cu(II), and Zn(II) in water, and can be used for removing Fe(III), Mn(II), Cu(II), and Zn(II).

[0028] (5) Compared with the traditional adsorbent, the prepared Mn-MOF can quickly and effectively remove Fe(III), Mn(II), Cu(II) and Zn(II) in 3h under strong acid conditions of pH=1-2, and the adsorption rate of Fe(III) is almost 100%, and the adsorption rates of Mn(II), Cu(II) and Zn(II) are as high as 97.8%, 99.4% and 99.7% respectively, which is extremely significant. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Process flow chart for the preparation method of the Mn-MOF material suitable for large-scale production of the application

[0030] Figure 2 Bar chart of adsorption rates (E%) of Fe(III), Mn(II), Cu(II) and Zn(II) in acidic water by the Mn-MOF material prepared by the method of the application DETAILED DESCRIPTION

[0031] In order to describe the application, the preparation method and application of the Mn-MOF material suitable for large-scale production of the application will be further described in detail below in combination with examples. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments not mentioned by the manufacturer are all conventional products that can be purchased on the market. The protection scope of the application is not limited by the following examples.

[0032] Example 1

[0033] In combination with the accompanying Figure 1 , the preparation method of the Mn-MOF material suitable for large-scale production of the application comprises the following steps:

[0034] (1) 0.0692g of manganese acetate tetrahydrate is weighed and dissolved in 18mL of N,N-dimethylformamide.

[0035] (2) 0.0332g of terephthalic acid is weighed and dissolved in 14mL of acetonitrile.

[0036] (3) The solutions in (1) and (2) are mixed, the molar ratio of manganese acetate tetrahydrate to terephthalic acid is close to 1.5:1, and are moved into a glass beaker.

[0037] (4) The operation parameters of the magnetic stirring heating instrument are set as follows: temperature 80℃, reaction time 60min, stirring speed 320rpm.

[0038] (5) The magnetic stirring rotor is placed in the sample, the temperature probe is connected, and the operation is started.

[0039] (6) After the synthesis is completed, the sample is removed and centrifuged. The separated solid is washed three times with ethanol and centrifuged three times. The synthesized Mn-MOF is dried in a vacuum drying oven at 100°C to obtain the Mn-MOF material.

[0040] In order to verify the adsorption rate (E%) of the Mn-MOF material prepared by the method of the present invention for Fe(III), Mn(II), Cu(II), and Zn(II) in acidic water, in this example, 0.01 g of Mn-MOF was weighed and added to an aqueous solution with a pH of 1.5 containing 10.4 mg / LFe(III), 10.6 mg / L Mn(II), 10.3 mg / L Cu(II), and 10.2 mg / L Zn(II). Ultrasonic-assisted mixing was performed, the reaction was allowed to stand for 3 hours, the loaded Mn-MOF was filtered out, and the adsorption rate (E%) was calculated.

[0041] Depend on Figure 2 As shown in the bar graph of the adsorption rate (E%) of the Mn-MOF material prepared by the method of the present invention for Fe(III), Mn(II), Cu(II) and Zn(II) in acidic water, the Mn-MOF material prepared by the method of the present invention has excellent adsorption performance for Fe(III), Mn(II), Cu(II) and Zn(II) in water, with the adsorption rate for Fe(III) being almost 100%, and the adsorption rates for Mn(II), Cu(II) and Zn(II) being as high as 97.8%, 99.4% and 99.7% respectively. The effect is extremely significant and can be used to remove Fe(III), Mn(II), Cu(II) and Zn(II), achieving unexpected technical effects.

[0042] Comparative Example 1

[0043] This comparative example adopts a synthesis method of Mn-MOF, which includes the following steps:

[0044] (1) Weigh 0.0492 g of manganese acetate tetrahydrate and dissolve it in 5 mL of N,N-dimethylformamide.

[0045] (2) Weigh 0.0332 g of terephthalic acid and dissolve it in 10 mL of water.

[0046] (3) The solutions in (1) and (2) were mixed so that the molar ratio of manganese acetate tetrahydrate to terephthalic acid was close to 1:1, and the mixture was transferred into a polytetrafluoroethylene-lined reactor and placed in a forced air drying oven.

[0047] (4) Set the operating parameters of the blast drying oven to 100°C and a reaction time of 7h.

[0048] (5) Synthesis is ended, the sample is taken out, centrifuged, the solid after separation is washed with ethanol for three times, centrifuged for three times, the synthesized Mn-MOF is dried in a vacuum drying oven at 70℃, and the Mn-MOF material is obtained.

[0049] Example 2

[0050] 0.01g of Mn-MOF is weighed and added into a water solution with pH = 1.8, containing 10mg / L of Fe(III), 10mg / L of Mn(II), 10mg / L of Cu(II), 10mg / L of Zn(II), and ultrasonic mixing is assisted, and the reaction is placed for 3h, the loaded Mn-MOF is filtered out, and the adsorption rate (E%) is calculated (see Table 1 for experimental data).

[0051] Table 1 is the test result of the Mn-MOF material prepared by the method of the embodiment of the present application as an adsorbent for removing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) in water.

[0052] Table 1 Mn-MOF as an adsorbent for removing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) in water

[0053]

[0054] Note: C0 is the initial concentration of the ion in the solution; C e is the concentration of the ion in the solution after the reaction.

Claims

1. A method for preparing Mn-MOF materials suitable for large-scale production, characterized in that The method comprises the following steps: dissolving a manganese salt in a solvent A and dissolving terephthalic acid in a solvent B; respectively introducing the two into a reaction vessel for mixing, heating and magnetic stirring, and after the reaction, washing and drying to obtain a Mn-MOF material; the molar ratio between the manganese salt and the terephthalic acid is (1-1.5):1, the temperature for heating and magnetic stirring is controlled at 70-90°C, the reaction time is controlled at 50-80 minutes, and the stirring rate is 250-400 rpm; the solvent A is N,N-dimethylformamide; and the solvent B is acetonitrile.

2. The method for preparing a Mn-MOF material suitable for large-scale production according to claim 1, wherein: The manganese salt is manganese acetate tetrahydrate.

3. The method for preparing a Mn-MOF material suitable for large-scale production according to claim 1, wherein: The manganese salt is manganese acetate tetrahydrate; the molar ratio between the manganese salt and terephthalic acid is (1.3-1.5):

1.

4. The method for preparing a Mn-MOF material suitable for large-scale production according to claim 1, wherein: The heating and stirring temperature was 80° C., the reaction time was 60 min, and the stirring rate was 320 rpm.

5. The use of a Mn-MOF material suitable for large-scale production according to claim 1, 2, 3 or 4, characterized in that: The Mn-MOF material is put into a water body containing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) at a pH of 1.0 to 2.0 as an adsorbent to adsorb Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) in the water body.

6. The use of a Mn-MOF material suitable for large-scale production according to claim 5, characterized in that: By detecting the metal ion concentration in water containing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II), the calculated mass of Mn-MOF was added to the water containing Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) at a solid-liquid ratio of 1:1 g / L at pH = 1.0-2.

0. The mixture was mixed and reacted for 3 hours, and the Mn-MOF loaded with Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) was filtered out.

7. The use of a Mn-MOF material suitable for large-scale production according to claim 6, characterized in that: The Fe(III) and / or Mn(II) and / or Cu(II) and / or Zn(II) solution used for treatment has an Fe(III) concentration of 0.1-10.4 mg / L, a Mn(II) concentration of 0.1-10.6 mg / L, a Cu(II) concentration of 0.1-10.3 mg / L, and a Zn(II) concentration of 0.1-10.2 mg / L.

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