A cellular glass fiber-based uiO-66 (zr) adsorbent and in-situ synthesis method and application

Abstract

This invention relates to the field of rotary dehumidification technology and discloses a honeycomb glass fiber-based UIO-66 (Zr) adsorbent, comprising: a honeycomb glass fiber substrate; and UIO-66 (Zr) crystals formed by coordination of terephthalic acid and zirconium salt in an aqueous phase with deionized water as the sole solvent, and in situ loaded on the surface of the honeycomb glass fiber substrate. An in-situ synthesis method for the honeycomb glass fiber-based UIO-66 (Zr) adsorbent includes the following steps: S1, taking terephthalic acid and alkali in a certain molar ratio. Utilizing the coordination mechanism of alkali-promoted water solubility of terephthalic acid and acid-controlled hydrolysis of zirconium salt, crystallization is completed under mild conditions, eliminating pollution risks, reducing energy consumption, and avoiding damage to the honeycomb glass fiber substrate structure and adhesives from high temperatures, ensuring carrier stability. This honeycomb glass fiber-based UIO-66 (Zr) adsorbent, its in-situ synthesis method, and its application, by using a pure aqueous phase synthesis process to replace the DMF organic solvent system, eliminates toxic high-boiling-point solvents from both the reaction principle and raw material perspectives.

Description

Technical Field

[0001] This invention relates to the field of rotary dehumidification technology, specifically to a honeycomb glass fiber-based UIO-66 (Zr) adsorbent, its in-situ synthesis method, and its application. Background Technology

[0002] Metal-organic frameworks (MOFs) have broad application prospects in gas adsorption, catalysis, and sensing due to their high specific surface area, tunable pore structure, and abundant active sites. Among them, UIO-66 (Zr), as a typical zirconium-based MOF, exhibits excellent hydrothermal stability, chemical stability, and structural controllability. Its regular micropore channels and high specific surface area make it an ideal adsorption material, widely used in water molecule adsorption and related fields. Furthermore, its adsorption performance can be optimized by controlling the preparation process.

[0003] However, existing synthesis systems heavily rely on N,N-dimethylformamide (DMF) as a solvent. DMF is reproductively toxic and is a flammable, difficult-to-recover organic solvent, posing serious environmental pollution risks, occupational health and safety hazards, and high wastewater treatment costs during large-scale industrial production. Furthermore, due to the high boiling point of DMF (153°C) and the fact that DMF systems typically require high temperatures (120°C) and long reaction times, subsequent complex solvent replacement or high-temperature activation steps are necessary to remove residual DMF from the pores, resulting in high energy consumption. Moreover, for glass fiber substrates, high temperature and high pressure conditions can easily lead to substrate structural deformation, adhesive failure, and difficulty in achieving uniform crystal growth. Summary of the Invention

[0004] (a) Technical problems to be solved: To address the shortcomings of existing technologies, this invention provides a honeycomb glass fiber-based UIO-66 (Zr) adsorbent, its in-situ synthesis method, and its application, solving the problems of existing synthesis methods mentioned in the background art, which rely on toxic organic solvents, have high energy consumption, and are prone to substrate deformation.

[0005] (II) Technical Solution: To achieve the above objectives, the present invention provides the following technical solution: A honeycomb glass fiber-based UIO-66 (Zr) adsorbent, comprising: Honeycomb fiberglass substrate; UIO-66 (Zr) crystals are formed by coordination of terephthalic acid and zirconium salt in an aqueous phase with deionized water as the sole solvent, and are in situ loaded onto the surface of the honeycomb glass fiber substrate.

[0006] A method for in-situ synthesis of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent includes the following steps: S1. Take a certain molar ratio of terephthalic acid and base, deprotonate the terephthalic acid under the action of the base, and then dissolve them together in the first deionized water to obtain solution A. Dissolve a certain molar ratio of zirconium salt and acid in the second deionized water to obtain solution B. Wait until the solid in solution A and solution B are completely dissolved and uniformly dispersed. S2. Pour the completely dissolved solution A obtained in S1 into solution B at a uniform speed, add a natural polymer thickener, and stir to obtain a uniform mixture. S3. The honeycomb glass fiber preform is immersed in the mixture prepared in S2, and the in-situ crystallization reaction is carried out at 40℃~150℃ for 10h~48h to obtain the crystallized substrate. S4. Take out the substrate prepared in S3, wash and dry it with deionized water to obtain honeycomb glass fiber-based UIO-66 (Zr) adsorbent.

[0007] Preferably, the base is an inorganic base or an organic amine; The inorganic base is one or more of sodium hydroxide, potassium hydroxide, and ammonia water; The organic amine is one or more of methylamine, ethylamine, propylamine, and triethylamine.

[0008] Preferably, the molar ratio of the terephthalic acid, the alkali, and the first deionized water is 1:1 to 4:60 to 130.

[0009] Preferably, the zirconium salt is any one of zirconium tetrachloride, zirconium oxychloride octahydrate, zirconium nitrate, and zirconium sulfate.

[0010] Preferably, the acid is an inorganic acid or an organic acid; The inorganic acid is one or more of hydrochloric acid, nitric acid, and sulfuric acid; The organic acid is one or more of formic acid, acetic acid, benzoic acid, and trifluoroacetic acid.

[0011] Preferably, the molar ratio of the zirconium salt, the acid, and the second deionized water is 1:5 to 25:60 to 120.

[0012] Preferably, the natural polymer thickener is a natural polymer glue, and the amount of the polymer thickener added is 0.2% to 2% of the total mass of the mixture.

[0013] Application of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent in the preparation of a low-temperature desorption and dehumidification rotor.

[0014] (III) Beneficial Effects: The honeycomb glass fiber-based UIO-66 (Zr) adsorbent, its in-situ synthesis method, and its application provided by this invention have the following beneficial effects: 1. This invention relates to a honeycomb fiberglass-based UIO-66 (Zr) adsorbent, its in-situ synthesis method, and its application. By using a pure aqueous phase synthesis process to replace the DMF organic solvent system, toxic high-boiling-point solvents are eliminated from the reaction principle and raw materials. The crystallization is completed under mild conditions by utilizing the coordination mechanism of alkali-promoted water solubility of terephthalic acid and acid-controlled hydrolysis of zirconium salt. This eliminates pollution risks, reduces energy consumption, and avoids damage to the honeycomb fiberglass substrate structure and adhesives caused by high temperatures, thus ensuring the stability of the carrier.

[0015] 2. This invention relates to a honeycomb glass fiber-based UIO-66 (Zr) adsorbent, its in-situ synthesis method, and its application. By loading UIO-66 (Zr) crystals in-situ onto a honeycomb glass fiber substrate, and relying on the three-dimensional porous framework of glass fiber to provide a uniform growth interface, the adhesion of the precursor liquid is regulated by a thickener, so that the crystals and the substrate interface are tightly bonded and uniformly distributed, thereby solving the problem of powder agglomeration and shedding, and constructing a continuous mass transfer channel to improve adsorption stability and water vapor mass transfer efficiency.

[0016] 3. This invention relates to a honeycomb glass fiber-based UIO-66 (Zr) adsorbent, its in-situ synthesis method, and its application. By controlling the aqueous phase synthesis parameters, the pore structure and hydrophilic properties of UIO-66 (Zr) are optimized. The nucleation and growth of crystals are controlled by the acid-base ratio and crystallization conditions, thereby optimizing the micropore distribution and the number of active sites. This enhances the water vapor adsorption capacity from the adsorption principle. At the same time, the composite structure reduces the activation energy of water molecule desorption, achieving a synergy between high hygroscopicity and low regeneration energy consumption. Attached Figure Description

[0017] Figure 1 The water vapor isothermal adsorption curves for Comparative Example 1 and Example 1 of this invention are shown below. Figure 2 The X-ray diffraction spectra of the samples from Examples 1 and 7 of this invention are shown below. Figure 3 The nitrogen adsorption-desorption isotherms and micropore size distribution diagrams for Comparative Example 1 and Example 1 of the present invention are shown. Figure 4 This is a summary chart showing the loading amount and moisture absorption rate at 25°C and 65%RH of the honeycomb glass fiber-based UIO-66 (Zr) adsorbents prepared in Examples 2, 4 to 17. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 A honeycomb glass fiber-based UIO-66 (Zr) adsorbent, its in-situ synthesis method, and its application, according to embodiments of the present invention, will be described in detail below: A honeycomb glass fiber-based UIO-66 (Zr) adsorbent, comprising: Honeycomb fiberglass substrate has the advantages of a three-dimensional interconnected porous structure, high specific surface area, lightweight and high strength, good corrosion resistance and low cost. It also has good support performance and dispersion characteristics, providing a stable support framework and reaction interface for the in-situ growth of UIO-66 (Zr) crystals, and adsorbing water molecules through its own microporous channels.

[0020] UIO-66 (Zr) crystals are formed by coordination of terephthalic acid and zirconium salt in an aqueous phase with deionized water as the sole solvent. This completely replaces DMF with deionized water, avoiding the high-temperature and high-pressure conditions (≥120℃) required in traditional processes due to the high boiling point of DMF (153℃). This prevents structural deformation of the glass fiber substrate or adhesive failure during the synthesis process. The UIO-66 (Zr) crystals are in situ loaded onto the surface of the honeycomb glass fiber substrate.

[0021] Example 2 refer to Figures 1 to 4 A method for in-situ synthesis of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent includes the following steps: S1. Take a certain molar ratio (to ensure that the sparingly soluble terephthalic acid is fully converted into water-soluble terephthalate) of 2g terephthalic acid and alkali (1g sodium hydroxide), and dissolve the terephthalic acid together in the first deionized water (20ml) after the terephthalic acid is deprotonated by the alkali to obtain solution A. Dissolve a certain molar ratio of zirconium salt (4g zirconium oxychloride octahydrate) and acid (10mL acetic acid) in the second deionized water (20ml) to obtain solution B. Wait until the solid in solution A and solution B are completely dissolved and uniformly dispersed. S2. Pour the completely dissolved solution A obtained in S1 into solution B at a uniform speed, add natural polymer thickener (0.4g of chitosan), the amount of which is 0.2% to 2% of the total mass of the mixture, and stir to obtain a uniform mixture. If the amount of natural polymer thickener added is less than 0.2%, the amount of adhesive coating will not be significantly improved, and if it is more than 2%, it will easily lead to an excessively thick and uneven coating layer.

[0022] S3. The honeycomb glass fiber preform is immersed in the mixture prepared in S2 and subjected to in-situ crystallization reaction at 80°C for 24 hours to obtain a crystallized substrate. S4. Take out the substrate prepared in S3, wash and dry it with deionized water (100°C) to obtain honeycomb glass fiber-based UIO-66 (Zr) adsorbent. The washing process needs to be repeated more than three times to completely remove unreacted terephthalic acid, zirconium salt and by-product salts, and ensure the purity and unobstructed pores of the final honeycomb glass fiber-based UIO-66 (Zr) adsorbent.

[0023] The alkali is either an inorganic alkali or an organic amine, with inorganic alkalis being preferred because they are cheaper and have no volatile toxicity.

[0024] The inorganic base is one or more of sodium hydroxide, potassium hydroxide, and ammonia water; The organic amine is one or more of methylamine, ethylamine, propylamine, and triethylamine.

[0025] The molar ratio of the terephthalic acid, the base, and the first deionized water is 1:2.08:92.6.

[0026] The zirconium salt is any one of zirconium tetrachloride, zirconium oxychloride octahydrate, zirconium nitrate, and zirconium sulfate. Zirconium oxychloride octahydrate (ZrOCl2·8H2O) has the best solubility in water, is relatively inexpensive, and has low corrosiveness to equipment, making it the preferred zirconium source.

[0027] The acid is an inorganic acid or an organic acid; The inorganic acid is one or more of hydrochloric acid, nitric acid, and sulfuric acid; The organic acid is one or more of formic acid, acetic acid, benzoic acid, and trifluoroacetic acid, among which formic acid and acetic acid are mild and easy to elute, and are preferred acids.

[0028] The molar ratio of the zirconium salt, the acid, and the second deionized water is 1:14.1:89.6.

[0029] The natural polymer thickener is a natural polymer gum (it is non-toxic and easily degradable, and will not introduce impurities that are difficult to remove during the crystallization reaction). The natural polymer gum can be selected from one or more of xanthan gum, sodium alginate, guar gum, gelatin, and chitosan.

[0030] The test results showed that the adsorbent synthesized in Example 2 had a loading of 57.7% and a moisture absorption rate of 18.5% at 25°C and 65% RH.

[0031] Example 3 Application of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent in the preparation of a low-temperature desorption dehumidification rotor. Specifically, it can be directly used to prepare a low-temperature desorption dehumidification rotor, suitable for various low-energy dehumidification scenarios such as industrial deep dehumidification, air conditioning fresh air dehumidification, and warehouse moisture prevention.

[0032] In application, the adsorbent is processed into a honeycomb-shaped rotor core, utilizing its three-dimensional interconnected porous structure and high specific surface area as the core functional layer for rotor dehumidification. During dehumidification, humid air flows through the rotor, and the adsorbent surface and microporous channels, thanks to the strong hydrophilic adsorption properties of UIO-66 (Zr), rapidly capture water molecules in the air, achieving efficient air drying. After adsorption saturation, low-temperature hot air is used to reverse-purge the rotor for desorption. Compared to traditional adsorbents, the honeycomb glass fiber-based UIO-66 (Zr) adsorbent has a lower desorption temperature and higher desorption efficiency, significantly reducing regeneration energy consumption while avoiding substrate aging and performance degradation caused by high temperatures.

[0033] In practical applications, the honeycomb fiberglass substrate possesses strong structural strength and resistance to pulverization, enabling long-term stable operation and reducing maintenance costs. Furthermore, the adsorbent prepared using the aqueous synthesis process leaves no organic solvent residue, making it environmentally friendly and suitable for dehumidification environments with high cleanliness requirements, such as food processing and pharmaceutical production, demonstrating significant industrial application value.

[0034] Example 4 The method is essentially the same as in Example 2, except that the alkali used is 1g of potassium hydroxide. Testing showed that the adsorbent synthesized in Example 4 had a loading of 59.8% and a moisture absorption rate of 17.8% at 25°C and 65% RH.

[0035] Example 5 The method is essentially the same as Example 2, except that the molar ratio of terephthalic acid, alkali, and first deionized water is 1:1.5:92.6; and the alkali is 0.72g of sodium hydroxide. Testing showed that the adsorbent synthesized in Example 5 had a loading of 52.2% and a moisture absorption rate of 13.8% at 25°C and 65% RH.

[0036] Example 6 The method is essentially the same as in Example 2, except that the molar ratio of terephthalic acid, alkali, and first deionized water is 1:3.5:92.6; and the alkali is 1.69 g of sodium hydroxide. Testing showed that the adsorbent synthesized in Example 6 had a loading of 56.2% and a moisture absorption rate of 11.2% at 25°C and 65% RH.

[0037] Example 7 The experiment was essentially the same as in Example 2, except that the molar ratio of terephthalic acid, alkali, and first deionized water was 1:2.08:83.3, and the amount of first deionized water added was 18 ml. Testing showed that the adsorbent synthesized in Example 7 had a loading of 63% and a moisture absorption rate of 16.4% at 25°C and 65% RH.

[0038] Example 8 The method is essentially the same as in Example 2, except that the molar ratio of terephthalic acid, alkali, and first deionized water is 1:2.08:111, and the amount of first deionized water added is 24 ml. Testing showed that the adsorbent synthesized in Example 8 had a loading of 40.7% and a moisture absorption rate of 14.1% at 25°C and 65% RH.

[0039] Example 9 The method is essentially the same as in Example 2, except that the acid used is 10 ml of formic acid. Testing showed that the adsorbent synthesized in Example 9 had a loading of 56.5% and a moisture absorption rate of 18.1% at 25°C and 65% RH.

[0040] Example 10 The method is essentially the same as Example 2, except that the molar ratio of zirconium salt, acid, and second deionized water is 1:8.5:89.6; the zirconium salt is 4g of zirconium oxychloride octahydrate; the acid is 6mL of acetic acid; and the amount of second deionized water added is 20mL. The adsorbent synthesized in Example 10 had a loading of 54.8% and a moisture absorption rate of 12.5% ​​at 25°C and 65% RH.

[0041] Example 11 The method is essentially the same as Example 2, except that the molar ratio of zirconium salt, acid, and second deionized water is 1:16.9:89.6; the zirconium salt is 4g of zirconium oxychloride octahydrate; the acid is 12mL of acetic acid; and the amount of second deionized water added is 20mL. The adsorbent synthesized in Example 11 had a loading of 57.7% and a moisture absorption rate of 14.7% at 25°C and 65% RH.

[0042] Example 12 The method is essentially the same as Example 2, except that the molar ratio of zirconium salt, acid, and second deionized water is 1:14.1:80.6; the zirconium salt is 4g of zirconium oxychloride octahydrate; the acid is 10mL of acetic acid; and the amount of second deionized water added is 18mL. The adsorbent synthesized in Example 12 had a loading of 62.3% and a moisture absorption rate of 13.9% at 25°C and 65% RH.

[0043] Example 13 The method is essentially the same as Example 2, except that the molar ratio of zirconium salt, acid, and second deionized water is 1:14.1:107.5; the zirconium salt is 4g of zirconium oxychloride octahydrate; the acid is 10mL of acetic acid; and the amount of second deionized water added is 24mL. The adsorbent synthesized in Example 13 had a loading of 48.9% and a moisture absorption rate of 12.6% at 25°C and 65% RH.

[0044] Example 14 The results are essentially the same as in Example 2, except that the natural polymeric thickener is 0.3g of chitosan. Testing showed that the adsorbent synthesized in Example 14 had a loading of 49.8% and a moisture absorption rate of 14.3% at 25°C and 65% RH.

[0045] Example 15 The results are basically the same as in Example 2, except that the natural polymer thickener is 0.7g of chitosan. The loading of the adsorbent synthesized in Example 15 was 59.2%, and the moisture absorption rate was 15.2% at 25°C and 65% RH.

[0046] Example 16 The process was essentially the same as in Example 2, except that the in-situ crystallization conditions were: a reaction at 60°C for 36 hours under solvothermal conditions. Testing showed that the adsorbent synthesized in Example 16 had a loading of 59.5% and a moisture absorption rate of 11.9% at 25°C and 65% RH.

[0047] Example 17 The process was essentially the same as in Example 2, except that the in-situ crystallization conditions were: a reaction at 120°C for 15 hours under solvothermal conditions. The adsorbent synthesized in Example 17 had a loading of 58.6% and a moisture absorption rate of 12.8% at 25°C and 65% RH.

[0048] Comparative Example 1 This is essentially the same as Example 4, except that: no honeycomb fiberglass preform was used. Testing revealed that: From the accompanying drawings, embodiments, and comparative examples, it can be concluded that: As can be seen from Examples 2, 4 and Comparative Example 1, the present invention uses a pure aqueous phase synthesis process, which does not require toxic solvents such as DMF, and can stably prepare honeycomb glass fiber-based UIO-66 (Zr) adsorbent. The process is green and environmentally friendly, avoiding the pollution, high energy consumption and substrate deformation problems of traditional processes. As can be seen from the comparison of Examples 2, 4 to 15, by using sodium hydroxide, zirconium oxychloride octahydrate, acetic acid and chitosan as raw materials and controlling the reasonable ratio and dosage, an adsorbent with high loading capacity and high hygroscopicity can be obtained. Furthermore, improper raw material ratio will reduce the crystallization quality and adsorption performance. Depend on Figure 4 Examples 2, 16, and 17 show that a crystallization temperature of 60℃~120℃ and a crystallization time of 15h~36h are the optimal conditions. Inappropriate crystallization temperature or time can lead to insufficient crystallization or grain agglomeration, affecting product performance. Depend on Figure 1 , Figure 2 , Figure 3The characterization results from Examples 1 and 7 and Comparative Example 1 show that the honeycomb glass fiber load does not damage the intrinsic microporous structure of UIO-66 (Zr), and its adsorption performance is comparable to that of pure powder. Moreover, the structure is stable and not easy to shed powder, making it more suitable for industrial applications of low-temperature desorption and dehumidification rotors.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A honeycomb glass fiber-based UIO-66 (Zr) adsorbent, characterized in that: include: Honeycomb fiberglass substrate; UIO-66 (Zr) crystals are formed by coordination of terephthalic acid and zirconium salt in an aqueous phase with deionized water as the sole solvent, and are in situ loaded onto the surface of the honeycomb glass fiber substrate.

2. A method for in-situ synthesis of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent, characterized in that, Includes the following steps: S1. Take a certain molar ratio of terephthalic acid and base, deprotonate the terephthalic acid under the action of the base, and then dissolve them together in the first deionized water to obtain solution A. Dissolve a certain molar ratio of zirconium salt and acid in the second deionized water to obtain solution B. Wait until the solid in solution A and solution B are completely dissolved and uniformly dispersed. S2. Pour the completely dissolved solution A obtained in S1 into solution B at a uniform speed, add a natural polymer thickener, and stir to obtain a uniform mixture. S3. The honeycomb glass fiber preform is immersed in the mixture prepared in S2, and the in-situ crystallization reaction is carried out at 40℃~150℃ for 10h~48h to obtain the crystallized substrate. S4. Take out the substrate prepared in S3, wash and dry it with deionized water to obtain honeycomb glass fiber-based UIO-66 (Zr) adsorbent.

3. The in-situ synthesis method of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent according to claim 2, characterized in that: The base is an inorganic base or an organic amine; The inorganic base is one or more of sodium hydroxide, potassium hydroxide, and ammonia water; The organic amine is one or more of methylamine, ethylamine, propylamine, and triethylamine.

4. The in-situ synthesis method of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent according to claim 2, characterized in that: The molar ratio of the terephthalic acid, the alkali, and the first deionized water is 1:1 to 4:60 to 130.

5. The in-situ synthesis method of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent according to claim 2, characterized in that: The zirconium salt is any one of zirconium tetrachloride, zirconium oxychloride octahydrate, zirconium nitrate, and zirconium sulfate.

6. The in-situ synthesis method of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent according to claim 2, characterized in that: The acid is an inorganic acid or an organic acid; The inorganic acid is one or more of hydrochloric acid, nitric acid, and sulfuric acid; The organic acid is one or more of formic acid, acetic acid, benzoic acid, and trifluoroacetic acid.

7. The in-situ synthesis method of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent according to claim 2, characterized in that: The molar ratio of the zirconium salt, the acid, and the second deionized water is 1:5-25:60-120.

8. The in-situ synthesis method of a honeycomb glass fiber-based UIO-66 (Zr) adsorbent according to claim 2, characterized in that: The natural polymer thickener is a natural polymer glue, and the amount of the polymer thickener added is 0.2% to 2% of the total mass of the mixture.

9. The application of the honeycomb glass fiber-based UIO-66 (Zr) adsorbent as described in claim 1 in the preparation of a low-temperature desorption and dehumidification rotor.

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