CN115838481A - A kind of preparation method and application of Zr-based metal organic framework UiO-66 - Google Patents

Abstract

The invention relates to the technical field of metal-organic framework materials, in particular to a preparation method and application of a Zr-based metal-organic framework material UiO-66, wherein the Zr-based metal-organic framework material UiO-66 comprises the following raw materials, zirconium tetrachloride, terephthalic acid and a multidimensional regulator, the molar ratio is 1/x/35, and the preparation method comprises the following steps: s1, adding zirconium tetrachloride, terephthalic acid (BDC), N-dimethylformamide and multidimensional regulators with different amounts into a 100 mL hollyhock bottle, uniformly mixing, and performing ultrasonic treatment until the solid is completely dissolved; s2, reacting 48 h in a 120 ℃ oven, and centrifuging and collecting precipitates; s3, cleaning with nitrogen-nitrogen dimethylformamide for three times, replacing with methanol for three times, dissolving unreacted raw materials, and replacing with a low-boiling-point solvent; s4, heating and activating 12 h at 250 ℃ under vacuum. According to the invention, by utilizing the exposed metal active sites and the pore diameter expanded to the mesoporous region, high-efficiency specific adsorption can be effectively realized on the negative electricity low-concentration high-risk emerging pollutants in the water body, and the method has the advantages of good cyclicity, easiness in regeneration and strong stability.

Description

A kind of preparation method and application of Zr-based metal organic framework UiO-66

technical field

The invention relates to the technical field of metal organic framework materials, in particular to a preparation method and application of a Zr-based metal organic framework UiO-66.

Background technique

PPCPs are a class of emerging environmental pollutants with a wide variety and a large number, including drugs, cosmetics, veterinary drugs, fungicides, disinfectants, pesticides and so on. Due to its low concentration in the environment, with the development of detection technology, the presence of PPCPs was first detected in the environment in the 1980s. Many studies have shown that PPCPs have widely existed in rivers and lakes, and the existence of PPCPs has been detected in many famous rivers in the world. Studies have reported that PPCPs have potential risks, chronic toxicity, bioaccumulation, and long-term accumulation will cause serious consequences that cannot be ignored. However, traditional removal methods cannot effectively remove PPCPs. Therefore, finding a suitable material to achieve specific adsorption and degradation of low-concentration and high-risk PPCPs in the environment has become a research hotspot in recent years. It is known from research that an excellent adsorption material should satisfy the characteristics of high specific surface area and abundant active sites, and MOFs just have such advantages.

Metal-organic frameworks (MOFs) are crystalline porous materials with promising applications. The pore size and shape of MOFs can be tuned by changing the inorganic units or organic ligands, and this controllable adjustment makes MOFs attract extensive attention. MOFs have important applications in the fields of adsorption, separation and storage of gases and vapors. In recent years, more and more researches have focused on MOFs to remove pollutants in water, such as heavy metal ions, benzene, dyes, etc.

Zr-MOF is a class with excellent stability among many MOFs. It has high specific surface area and porosity, exposed active sites, clear structure and convenient modification, and has photocatalytic potential. Therefore, it is used in the removal of emerging pollutants in water It has great application prospects.

The MOF in the mesoporous region is more compatible with the molecular size of PPCPs, and it is easy to synthesize, has high stability, and has a clear structure. UiO-66 with high specific surface area and porosity is a Zr-MOF in the mesoporous region, so UiO-66 is in the adsorption There is still much room for improvement in the effect of removing PPCPs.

Contents of the invention

In order to solve at least one of the above-mentioned technical problems, the present invention proposes a preparation method and application of a Zr-based metal-organic framework UiO-66. By adding a multidimensional regulator to the precursor synthesized by the metal-organic framework material, nitrogen nitrogen dimethyl The metal-organic framework materials with continuously adjustable defect structures were obtained by uniform mixing in formamide solution and by solvothermal method. The invention utilizes the exposed metal active sites and the pore diameter extended to the mesoporous region, can effectively achieve high-efficiency and specific adsorption on negatively charged, low-concentration, high-dangerous emerging pollutants in water bodies, and has good circulation, easy regeneration, and strong stability.

In order to achieve the above object, the present invention provides a method for preparing Zr-based metal-organic framework UiO-66, which includes the following raw materials: zirconium tetrachloride, terephthalic acid and multidimensional regulator, and its molar ratio is 1/ x/35, wherein x=0.3,0.5,0.8,1.0, its preparation method comprises the following steps: comprising the following steps:

S1, add zirconium tetrachloride, terephthalic acid (BDC), and nitrogen-nitrogen dimethylformamide and different amounts of multidimensional regulators into a 100 mL Shu Niu bottle and mix evenly, sonicate until the solids are completely dissolved;

S2, react in an oven at 120 °C for 48 h, and collect the precipitate by centrifugation;

S3, washing with nitrogen nitrogen dimethylformamide three times, replacing with methanol three times, dissolving unreacted raw materials, and replacing low boiling point solvent;

S4, activated by heating under vacuum at 250 °C for 12 h.

Preferably, the coordination numbers of zirconium tetrachloride and terephthalic acid in S1 are unsaturated coordination.

Preferably, said x=0.3.

Preferably, the multidimensional regulator is a unilateral carboxylic acid.

Preferably, the unilateral carboxylic acid is one of acetic acid, n-pentanoic acid, n-octanoic acid, n-dodecanoic acid, n-tetradecanoic acid and n-heptadecanoic acid.

The second aspect of the present invention is to provide the application of Zr-based metal-organic framework UiO-66 in removing emerging pollutants in water bodies.

Compared with the prior art, the present invention has the following beneficial effects:

In the present invention, the metal-organic framework material with a continuously adjustable defect structure is obtained by adding the multi-dimensional regulator to the precursor synthesized by the metal-organic framework material, uniformly mixing it in the nitrogen-nitrogen dimethylformamide solution, and using the solvothermal method . The invention utilizes the exposed metal active sites and the pore diameter extended to the mesoporous region, can effectively achieve high-efficiency and specific adsorption on negatively charged, low-concentration, high-dangerous emerging pollutants in water bodies, and has good circulation, easy regeneration, and strong stability.

By introducing unilateral carboxylic acid modulators of different sizes, and designing the weak, medium and strong three competitive coordination environments of the modulator and BDC in the resynthesis, and reacting in a programmable heating and cooling oven for 48 hours, the realization of the The continuous regulation of Zr-MOF's pore size range, specific surface area and other properties optimizes the adsorption effect of Zr-MOF on PPCPs.

As the size of the modulator increases, the pore size distribution of the material shows an increasing trend, and the adsorption rate of the material to ibuprofen drug molecules is significantly improved, indicating that this strategy has indeed improved the adsorption of emerging pollutants by Zr-MOF Effect.

Description of drawings

1-4 are X-ray powder diffraction patterns of UiO-66 materials synthesized with different modulators in Example 1 of the present invention.

5-10 are the nitrogen adsorption and desorption test curves and pore size distribution diagrams of UiO-66 materials synthesized with different regulators in Example 1 of the present invention.

11-12 are scanning electron micrographs in Example 1 of the present invention.

Fig. 13 is a thermogravimetric diagram of UiO-66 material synthesized with different modulators in Example 1 of the present invention.

Fig. 14 is the elemental analysis of the UiO-66 material synthesized by different modulators in Example 1 of the present invention.

15-16 are graphs of adsorption kinetics data of UiO-66 materials synthesized by different modulators in Example 1 of the present invention, using IBU as a model compound molecule.

Implementation

In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described The embodiments are only some of the embodiments of the present invention, but not all of the embodiments of the present invention.

Please refer to Fig. 1-16, the part instrument information that adopts in the embodiment of the present invention is as follows:

Infrared spectrometer, model: Bruker Focus D8; manufacturer: Bruker, Germany;

X-ray powder diffractometer, model: MiniFlex 600 diffractometer, manufacturer: Japan Rigaku Company;

Scanning electron microscope, model: JEM-2010, manufacturer: Hitachi, Japan;

Elemental analyzer, model: VARIO EL-III, manufacturer: German Elementar Analysensysteme GmbH company;

Nitrogen adsorption and pore size analyzer, model: Prodigy 7, manufacturer: Leeman Company;

Thermogravimetric thermal differential comprehensive thermal analyzer, model: TG-DTA 6200, manufacturer: Hitachi Seiko;

High performance liquid chromatography, model: LC-20, manufacturer: Shimadzu.

Example 1

This example provides a preparation method and application of a Zr-based metal-organic framework UiO-66,

Specifically, its preparation method includes the following steps: 0.16 g of zirconium tetrachloride, 0.034 g, 0.057 g, 0.091 g, 0.114 g of terephthalic acid (BDC), 40 mL of nitrogen nitrogen dimethylformamide and different amounts of The regulator was added to a 100 mL Shu Niu bottle, and ultrasonicated for 20 min until all the solids were dissolved. React in an oven at 120 °C for 48 h, collect the precipitate by centrifugation, wash with nitrogen nitrogen dimethylformamide three times, and replace with methanol three times to dissolve unreacted raw materials, and replace the low boiling point solvent, and activate by heating at 250 °C under vacuum for 12 h.

The dosage of regulator, as shown in the table:

Experimental example 1

Figures 1-4 are the X-ray powder diffraction patterns of the UiO-66 material synthesized by different regulators in Example 1 of the present invention, which can completely correspond to the simulated pattern, proving the successful synthesis of the UiO-66 material.

Figures 5-10 are the nitrogen adsorption and desorption test curves and pore size distribution diagrams of UiO-66 materials synthesized by different modifiers in Example 1 of the present invention. As the size of the modifier increases, the specific surface area generally increases first and then steady law. The pore size distribution always showed an increasing trend.

Figures 11-12 are scanning electron microscope images of Example 1 of the present invention. It can be found that under the same regulator condition, the size of the material tends to become smaller as the competitive coordination environment increases. In a strongly competitive coordination environment, the size of the material gradually decreases as the size of the modulator increases.

Figure 13 is the thermogravimetric diagram of the UiO-66 material synthesized by different regulators in Example 1 of the present invention. It can be seen that the thermal stability of the same regulator decreases with the enhancement of the competitive coordination environment, and the different regulators As the size of the agent increases, the thermal stability decreases.

Figure 14 is the elemental analysis of the UiO-66 material synthesized with different regulators in Example 1 of the present invention, it can be seen that the gradient of C element decreases.

Figures 15-16 are the adsorption kinetics data graphs of the UiO-66 material synthesized by different regulators in Example 1 of the present invention, using IBU as the model compound molecule, to evaluate the adsorption performance of the present invention. For the acetic acid group, the adsorption rate tended to increase with the strengthening of the regulator competition environment. The valeric acid, caprylic acid, and lauric acid groups also showed the same pattern. The kinetic constants of the lauric acid group were 13.33-28.33 times higher than those of the acetic acid group. Under the same competitive coordination environment, with the increase of the regulator size, the adsorption rate was significantly improved, and the rate constant of the lauric acid group was 22 times that of the acetic acid group.

The above is the specific implementation of the embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present application.

Claims (6)

1. The preparation method of the Zr-based metal organic framework UiO-66 is characterized by comprising the following raw materials: zirconium tetrachloride, terephthalic acid and a multidimensional regulator, wherein the molar ratio of the zirconium tetrachloride to the terephthalic acid to the multidimensional regulator is 1/x/35, wherein x =0.3,0.5,0.8,1.0, and the preparation method comprises the following steps:

s1, adding zirconium tetrachloride, terephthalic acid (BDC), N-dimethylformamide and multidimensional regulators with different amounts into a 100 mL hollyhock bottle, uniformly mixing, and performing ultrasonic treatment until the solid is completely dissolved;

s2, reacting 48 h in an oven at 120 ℃, and centrifuging and collecting precipitates;

s3, cleaning with nitrogen-nitrogen dimethylformamide for three times, replacing with methanol for three times, dissolving unreacted raw materials, and replacing with a low-boiling-point solvent;

s4, heating and activating 12 h under vacuum at 250 ℃.

2. The method of claim 1, wherein the coordination number of zirconium tetrachloride and terephthalic acid in S1 is unsaturated.

3. The method of claim 2, wherein x =0.3, for preparing the Zr-based metal-organic framework UiO-66.

4. The method of claim 1, wherein the multi-dimensional adjusting agent is a mono-carboxylic acid.

5. The method for preparing the Zr-based metal organic framework UiO-66 according to claim 4, wherein said mono-side carboxylic acid is one of acetic acid, n-pentanoic acid, n-octanoic acid, n-dodecanoic acid, n-tetradecanoic acid, and n-heptadecanoic acid.

6. Use of the Zr-based metal organic framework UiO-66 prepared by the method of any one of claims 1 to 5 for removing emerging pollutants from a body of water.

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