Preparation method of TTSBI modified MOFs adsorbent as well as product and application of TTSBI modified MOFs adsorbent

Abstract

The invention provides a preparation method of a TTSBI modified MOFs adsorbent as well as a product and application of the TTSBI modified MOFs adsorbent. The preparation method comprises the following steps: adding chromic nitrate and terephthalic acid into a solvent, mixing, heating to 180-200 DEG C, preserving heat, cooling, centrifuging, collecting precipitate, adding a TTSBI solution, heating to 180-200 DEG C, preserving heat, cooling, washing, and drying to obtain the TTSBI modified MOFs adsorbent. According to the modified MOFs adsorbent, the adsorption capacity of the adsorbent on methyl ethyl ketone gas is remarkably improved, the water resistance test result shows that the modified MOFs adsorbent has good water stability, and the modified MOFs adsorbent also has very excellent repeated use stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of adsorbent preparation, and specifically relates to a preparation method, product and application of a TTSBI-modified MOF adsorbent. Background Art

[0002] MIL-101 is a metal-organic framework (MOF) material. The porous structure of MIL-101 provides it with a large surface area, which enables it to effectively capture and immobilize target molecules during the adsorption process, and can efficiently remove pollutants in the air and harmful substances in water. This not only contributes to environmental remediation work but also provides strong support for various industrial applications.

[0003] In the field of adsorption, MIL-101 has a wide range of applications. For example, MIL-101 can efficiently adsorb and recycle phosphate in water, providing a new approach for water resource protection and reuse. In addition, MIL-101 is also used for the adsorption and extraction of uranium. By combining with functional groups such as amidoxime groups or amino acids, highly efficient, highly selective and recyclable uranium adsorption materials are prepared, providing strong technical support for nuclear energy development and environmental protection.

[0004] However, the regeneration and recycling of MIL-101 adsorbents face certain challenges. In practical applications, the adsorbent needs to undergo multiple adsorption-desorption cycles to maintain its performance. The regeneration process may cause damage to the structure of MIL-101 or a decrease in performance, affecting its long-term use effect. Summary of the Invention

[0005] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments.

[0006] As one aspect of the present invention, the present invention provides a preparation method of a TTSBI-modified MOF adsorbent, which includes: adding chromium nitrate and terephthalic acid to a solvent and mixing them, heating to 180 - 200 °C, keeping warm, centrifuging to collect the precipitate after cooling, adding a TTSBI solution, heating to 180 - 200 °C and then keeping warm, washing and drying after cooling to obtain the TTSBI-modified MOF adsorbent;

[0007] Wherein, the TTSBI solution is obtained by adding 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane to a solvent.

[0008] As a preferred scheme of the preparation method of the TTSBI-modified MOF adsorbent according to the present invention: when adding chromium nitrate and terephthalic acid to a solvent and mixing them, the molar ratio of chromium nitrate to terephthalic acid is 1:0.8 - 1.2.

[0009] As a preferred embodiment of the preparation method of the TTSBI-modified MOF adsorbent of the present invention: chromium nitrate and terephthalic acid are added to a solvent and mixed, wherein the solvent includes water.

[0010] As a preferred embodiment of the preparation method of the TTSBI-modified MOF adsorbent of the present invention: heating to 180-200 °C and holding the temperature is carried out by heating at a heating rate of 2-3 °C / min, and the holding time is 6-8 h.

[0011] As a preferred embodiment of the preparation method of the TTSBI-modified MOF adsorbent of the present invention: the concentration of the TTSBI solution is 4-6 g / L.

[0012] As a preferred embodiment of the preparation method of the TTSBI-modified MOF adsorbent of the present invention: the solvent of the TTSBI solution includes N,N-dimethylformamide.

[0013] As a preferred embodiment of the preparation method of the TTSBI-modified MOF adsorbent of the present invention: the washing includes washing with N,N-dimethylformamide and ethanol respectively.

[0014] Beneficial effects of the present invention: The present invention uses 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane (TTSBI) to modify the MOF adsorbent, significantly improving the adsorption capacity of the adsorbent for methyl ethyl ketone gas. The water resistance test results of the modified MOF adsorbent of the present invention show that it has good water stability, and the modified MOF adsorbent also has very excellent reusability stability. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Among them:

[0016] Figure 1 It is a scanning electron microscope picture of the MOF adsorbent modified by 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane (TTSBI) in Example 15.

[0017] Figure 2 It is an infrared spectrum of the MOF adsorbent modified by TTSBI in Example 1.

[0018] Figure 3 It is the N2 adsorption-desorption isotherm of the MOF adsorbent modified by TTSBI in Example 1. Detailed Embodiments

[0019] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specifically describes the specific embodiments of the present invention in detail.

[0020] Example 1:

[0021] Weigh 4 g of chromium nitrate, 1.66 g of terephthalic acid, and 50 mL of deionized water, mix them in a beaker, and subject them to ultrasonic treatment for 30 min. After the chromium nitrate is fully dissolved, transfer the solution to a stainless-steel autoclave. Place the autoclave in an oven, with a heating rate of 2 °C / min, heat up to 200 °C, keep the temperature constant for 8 h, then gradually cool down to room temperature over 5 h. Centrifuge at 5000 rpm for 30 min, pour off the supernatant, transfer the precipitate to a 100 mL autoclave. Weigh 0.3 g of 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane (TTSBI), dissolve it in 50 mL of N,N-dimethylformamide solution, transfer the solution to the autoclave, place the autoclave in an oven, with a heating rate of 2 °C / min, heat up to 200 °C, keep the temperature constant for 8 h, and then slowly cool down to room temperature over 5 h. Take out the autoclave cooled to room temperature, stir the obtained solution thoroughly with a glass rod, transfer the thoroughly stirred solution to a 250 mL beaker, add N,N-dimethylformamide solution to the beaker to about 120 mL, then stir in a 60 °C water bath for 3 h. Centrifuge the mixture in the beaker at 5000 rpm for 30 min. After centrifugation, pour off the supernatant, add N,N-dimethylformamide solution to the centrifuge tube to about 30 mL, continue centrifugation for 10 min. After centrifugation, pour off the supernatant. Add a small amount of ethanol solution to wash the centrifuge tube, dissolve the product and transfer it to a 250 mL beaker, add ethanol to the beaker to about 130 mL, then stir in a 60 °C water bath for 3 h, repeat the washing 3 times, and dry the product in an oven at 60 °C overnight. After complete drying, transfer the product to a mortar, gently grind it for 2 min, then transfer it to a sample bottle and store it in a dry environment.

[0022] The adsorption capacity of the adsorbent for methyl ethyl ketone gas is measured to be 382 mg / g. After ten cycles of testing, the adsorbent shows excellent adsorption performance for methyl ethyl ketone, and the adsorption capacity remains above 90%, indicating excellent reusability stability.

[0023] When tested for water resistance with 30% water vapor content, the adsorption capacity of the adsorbent only loses 14%, indicating that the prepared adsorbent has good water stability.

[0024] Example 2:

[0025] Weigh 4 g of chromium nitrate, 1.66 g of terephthalic acid and 50 mL of deionized water, mix them in a beaker, and subject them to ultrasonic treatment for 30 min. After the chromium nitrate is fully dissolved, place it in a stainless-steel autoclave. Place the autoclave in an oven, with a heating rate of 2 °C / min, heat up to 200 °C, keep the temperature constant for 8 h, and then slowly cool down to room temperature over 5 h. Centrifuge at 5000 rpm for 30 min, pour off the supernatant, transfer the precipitate to a 100 mL autoclave. Weigh 0.2 g of 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane and dissolve it in 50 mL of N,N-dimethylformamide solution, transfer the solution to the autoclave, and the subsequent operations are the same as in Example 1. The adsorption capacity of the prepared adsorbent for methyl ethyl ketone is 369 mg / g.

[0026] Example 3:

[0027] Weigh 4 g of chromium nitrate, 1.66 g of terephthalic acid and 50 mL of deionized water, mix them in a beaker, and subject them to ultrasonic treatment for 30 min. After the chromium nitrate is fully dissolved, place it in a stainless-steel autoclave. Place the autoclave in an oven, with a heating rate of 2 °C / min, heat up to 200 °C, keep the temperature constant for 8 h, and then slowly cool down to room temperature over 5 h. Centrifuge at 5000 rpm for 30 min, pour off the supernatant, transfer the precipitate to a 100 mL autoclave. Weigh 0.3 g of 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane and dissolve it in 60 mL of N,N-dimethylformamide solution, transfer the solution to the autoclave, and the subsequent operations are the same as in Example 1. The adsorption capacity of the prepared adsorbent for methyl ethyl ketone is 373 mg / g.

[0028] Comparative Example 1:

[0029] Weigh 4 g of chromium nitrate, 1.66 g of terephthalic acid and 50 mL of deionized water and mix them in a beaker. Subject them to ultrasonic treatment for 30 min. After the chromium nitrate is fully dissolved, place it in a stainless-steel autoclave. Place the autoclave in an oven, with a heating rate of 2 °C / min, heat up to 200 °C, keep the temperature constant for 8 h, and then slowly cool down to room temperature over 5 h. Centrifuge at 5000 rpm for 30 min, pour off the supernatant, and transfer the product to a 100 mL autoclave. Weigh 0.3 g of 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane and dissolve it in 50 mL of deionized water, transfer the solution to the autoclave. The subsequent operations are the same as in Example 1.

[0030] The adsorption capacity of the prepared adsorbent for methyl ethyl ketone is 197 mg / g.

[0031] Use water vapor with a water content of 30% to test the water resistance of the adsorbent. The adsorption capacity of the adsorbent loses 63%, and the water resistance is poor.

[0032] Comparative Example 2:

[0033] Weigh 4 g of chromium nitrate, 1.66 g of terephthalic acid and 50 mL of deionized water, mix them in a beaker, and ultrasonically treat for 30 min to fully dissolve chromium nitrate, then place it in a stainless-steel autoclave. Place the autoclave in an oven, with a heating rate of 2 °C / min, heat up to 200 °C, keep the temperature constant for 8 h, then gradually cool down to room temperature over 5 h, centrifuge at 5000 rpm for 30 min, pour off the supernatant, transfer the precipitate to a 100 mL autoclave. Weigh 0.3 g of EDTA and dissolve it in 50 mL of N,N-dimethylformamide solution, then transfer the solution to the autoclave. The subsequent operations are the same as in Example 1. The adsorption capacity of the prepared adsorbent for methyl ethyl ketone is 146 mg / g.

[0034] Comparative Example 3:

[0035] Weigh 4 g of chromium nitrate, 1.66 g of terephthalic acid and 50 mL of deionized water, mix them in a beaker, and ultrasonically treat for 30 min to fully dissolve chromium nitrate, then place it in a stainless-steel autoclave. Place the autoclave in an oven, with a heating rate of 2 °C / min, heat up to 200 °C, keep the temperature constant for 8 h, then gradually cool down to room temperature over 5 h, centrifuge at 5000 rpm for 30 min, pour off the supernatant, transfer the precipitate to a 100 mL autoclave. Weigh 1 g of 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane and dissolve it in 50 mL of N,N-dimethylformamide solution, then transfer the solution to the autoclave. The subsequent operations are the same as in Example 1.

[0036] The adsorption capacity of the prepared adsorbent for methyl ethyl ketone is 267 mg / g. After five-cycle tests, the adsorption performance of the adsorbent for methyl ethyl ketone decreases to 50%, and the reusability stability is poor. A higher addition amount of TTSBI easily destroys the framework structure of the adsorbent, thus affecting the adsorption performance and stability.

[0037] Comparative Example 4:

[0038] Weigh 4 g of chromium nitrate, 1.66 g of terephthalic acid and 50 mL of deionized water, mix them in a beaker, and ultrasonically treat for 30 min to fully dissolve chromium nitrate, then place it in a stainless-steel autoclave. Place the autoclave in an oven, with a heating rate of 2 °C / min, heat up to 200 °C, keep the temperature constant for 8 h, then gradually cool down to room temperature over 5 h, centrifuge at 5000 rpm for 30 min, pour off the supernatant, transfer the precipitate to a 100 mL autoclave. Weigh 0.3 g of aminoethyl ethanolamine (AEEA) and dissolve it in 50 mL of N,N-dimethylformamide solution, then transfer the solution to the autoclave. The subsequent operations are the same as in Example 1. The adsorption capacity of the prepared adsorbent for methyl ethyl ketone is 152 mg / g.

[0039] As Figure 1 shown, the MOF adsorbent after TTSBI modification maintained the octahedral morphology of MIL-101. The adsorption capacity for methyl ethyl ketone gas was evaluated by the dynamic column breakthrough curve measurement method at room temperature and atmospheric pressure. The adsorption column used in the experiment was a heat-resistant quartz glass tube (inner diameter 7 mm, total length 490 mm). 0.05 g of the adsorbent of Examples 1 to 3 or Comparative Examples 1 to 4 was added to the adsorption column. The flow rate of the mixed gas stream composed of N2 and methyl ethyl ketone was 30 mL / min, and the concentration of methyl ethyl ketone was 500 ppm. The gas flow rate was controlled by a high-precision mass flow meter. The concentration of methyl ethyl ketone in the outlet gas was detected online by gas chromatography. In order to evaluate the cyclic stability of the adsorbent, continuous multiple cycles of methyl ethyl ketone adsorption and desorption experiments were carried out. After each adsorption performance evaluation test, the adsorbent was heated and purged with a nitrogen stream at 30 mL / min until no methyl ethyl ketone was detected in the outlet gas before re-evaluation. In order to evaluate the moisture resistance of the adsorbent, the influence of water vapor on the adsorption performance was evaluated by the water resistance test, and 3 vol.% of water vapor was introduced by adjusting the feed gas stream. The adsorption capacity of the MOF adsorbent after TTSBI modification was significantly higher than that of the unmodified MIL-101 for methyl ethyl ketone gas (257 mg / g), and at the same time, the adsorbent had high reusability stability.

[0040] It should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A preparation method of a TTSBI-modified MOF adsorbent, characterized in that: Chromium nitrate and terephthalic acid are added to a solvent and mixed, heated to 180 - 200 °C, kept warm, cooled, and the precipitate is collected by centrifugation. Then a TTSBI solution is added, heated to 180 - 200 °C and kept warm, cooled, washed, and dried to obtain a TTSBI-modified MOFs adsorbent; Among them, the TTSBI solution is obtained by adding 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane to a solvent.

2. The preparation method of the TTSBI-modified MOF adsorbent according to claim 1, wherein: When chromium nitrate and terephthalic acid are added to a solvent and mixed, the molar ratio of chromium nitrate to terephthalic acid is 1:0.8 - 1.

2.

3. The preparation method of the TTSBI-modified MOF adsorbent according to claim 1 or 2, characterized in that: When chromium nitrate and terephthalic acid are added to a solvent and mixed, the solvent includes water.

4. The preparation method of the TTSBI-modified MOF adsorbent according to claim 1 or 2, characterized in that: When heated to 180 - 200 °C and kept warm, it is heated at a heating rate of 2 - 3 °C / min, and the holding time is 6 - 8 h.

5. The preparation method of the TTSBI-modified MOFs adsorbent according to claim 1 or 2, characterized in that: The concentration of the TTSBI solution is 4 - 6 g / L.

6. The preparation method of the TTSBI-modified MOF adsorbent according to claim 1 or 2, characterized in that: The solvent of the TTSBI solution includes N,N-dimethylformamide.

7. The preparation method of the TTSBI-modified MOF adsorbent according to claim 1 or 2, characterized in that: The washing includes washing with N,N-dimethylformamide and ethanol respectively.

8. A TTSBI-modified MOFs adsorbent prepared by the preparation method of the TTSBI-modified MOFs adsorbent according to claim 1.

9. Application of the TTSBI-modified MOFs adsorbent prepared by the preparation method of the TTSBI-modified MOFs adsorbent according to claim 1 in adsorbing methyl ethyl ketone gas.

Images