A modified uiO-66 material, and a preparation method and application thereof

Abstract

The application relates to a modified UiO-66 material and a preparation method and application thereof. The method comprises the following steps: adding pure water into N,N-dimethylformamide and uniformly mixing to obtain a mixed solution A, then adding a zirconium metal source and an organic ligand into the mixed solution A and uniformly mixing to obtain a mixture B; carrying out hydrothermal reaction on the mixture B to obtain a reaction liquid; separating a reaction product from the reaction liquid and drying to obtain the modified UiO-66 material. The method is simple in synthesis and low in cost; after the UiO-66 is modified, basic sites and hydrophilicity are obviously increased, absorption of acid gases (such as acetaldehyde) is greatly increased, and degradation efficiency is obviously improved; compared with a traditional UiO-66 material, the modified UiO-66 material in the application realizes a breakthrough from nothing to something in the efficiency of photocatalytic degradation of acetaldehyde in a flow phase system.

Description

Technical Field

[0001] This invention belongs to the field of metal-organic framework (MOF) materials technology, and particularly relates to a modified UiO-66 material, its preparation method and application. Background Technology

[0002] Metal-organic frameworks (MOFs), as novel high-porosity crystalline coordination polymers, possess large specific surface areas, tunable porosity, and designable structures, and have been widely used in drug delivery, adsorption, gas storage / separation, sensing, and catalysis. Interior decoration, building materials (such as adhesives and coatings), and furniture continuously release various pollutants, especially volatile organic compounds (VOCs), including small-molecule aldehydes and large-molecule benzene compounds. UiO-66, as a catalyst rich in Lewis acidic sites, is widely used for the adsorption and catalysis of benzene compounds (Lewis bases). However, common aldehyde VOCs exhibit Lewis acidity; therefore, regulating the acid-base sites of UiO-66 has become an important research topic. Existing methods for introducing basic sites into UiO-66 mainly fall into two categories: one is to introduce alkali metals during the synthesis of UiO-66 to prepare bimetallic organic framework (MOF) materials; the other is to introduce organic ligands containing basic groups such as -NH2. However, the first method is relatively complicated to synthesize and involves the matching of two metals. The characterization of bimetals is also quite complex, making it difficult to determine whether it is a bimetallic MOF material or a mixture of two MOF materials. The second method has two problems: firstly, the cost of some basic ligands is relatively high; secondly, the introduction of basic groups will reduce the porosity of MOFs and often reduce the band gap of MOF materials. Photocatalysis requires that the band gap of the catalyst be sufficient for oxidation / reduction reactions in order to have a good catalytic effect.

[0003] In summary, it is essential to provide a modified UiO-66 material, its preparation method, and its applications. Summary of the Invention

[0004] In order to solve one or more technical problems existing in the prior art, the purpose of this invention is to provide a modified UiO-66 material, its preparation method and application.

[0005] In a first aspect, the present invention provides a method for preparing a modified UiO-66 material, the method comprising the following steps:

[0006] (1) Add pure water to N,N-dimethylformamide and mix evenly to obtain mixture A. Then add zirconium metal source and organic ligand to mixture A and mix evenly to obtain mixture B.

[0007] (2) The mixture B is subjected to a hydrothermal reaction to obtain a reaction solution;

[0008] (3) The reaction product is separated from the reaction solution and dried to obtain the modified UiO-66 material.

[0009] Preferably, the molar ratio of the pure water to the zirconium metal source is (3.5-40):1, more preferably (15-25):1.

[0010] Preferably, the zirconium metal source is one or more of zirconium tetrachloride, zirconium nitrate, and zirconium sulfate; and / or the organic ligand is terephthalic acid.

[0011] Preferably, the mass ratio of the zirconium metal source to the organic ligand is (0.3-0.4):(0.2-0.3); and / or the volume ratio of the pure water to the N,N-dimethylformamide is (0.1-1):50.

[0012] Preferably, the temperature of the hydrothermal reaction is 100–160°C, and the time of the hydrothermal reaction is 10–24 h.

[0013] Preferably, in step (3): the drying is vacuum drying at 80-120°C for 6-10 hours.

[0014] Preferably, the modified UiO-66 material is used for degrading acetaldehyde; the specific surface area of ​​the modified UiO-66 material is not less than 1000 m². 2 / g, preferably not less than 1200m 2 / g; the modified UiO-66 material adsorbs acetaldehyde in the mobile phase system at a rate of not less than 49 μmol / g, preferably not less than 150 μmol / g; and / or the contact angle between the modified UiO-66 material and water is not greater than 41°, preferably 20–25°.

[0015] The present invention provides, in a second aspect, a modified UiO-66 material prepared by the preparation method described in the first aspect.

[0016] In a third aspect, the present invention provides the application of the modified UiO-66 material prepared by the preparation method described in the first aspect in the degradation of acetaldehyde.

[0017] Preferably, the modified UiO-66 material has an acetaldehyde degradation efficiency of not less than 85% in a fixed-bed system; and / or the modified UiO-66 material has an acetaldehyde degradation efficiency of not less than 35% in a mobile phase system.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] (1) The method of the present invention is simple to synthesize and low in cost. For the first time in the synthesis process of traditional UiO-66 materials, alkaline sites are introduced by adding pure water. After modification, UiO-66 has significantly increased alkaline sites and hydrophilicity, greatly increasing the adsorption of acidic gases (such as acetaldehyde) and significantly improving the degradation efficiency. The modified UiO-66 material obtained is particularly suitable for photocatalytic degradation of acidic gases. At the same time, the modification method of the present invention has no significant effect on the band gap of the UiO-66 material itself.

[0020] (2) The modified UiO-66 material prepared in this invention increases the proportion of mesopores and the specific surface area, which is beneficial to gas adsorption and mass transfer. It increases the number of alkaline sites and hydrophilicity, which is particularly beneficial to the adsorption of acetaldehyde. The adsorption performance of acetaldehyde is greatly increased. The adsorption capacity of acetaldehyde in the mobile phase system increases from 0.6 μmol / g before modification to more than 159.1 μmol / g after modification. In some preferred embodiments of this invention, the modified UiO-66 material prepared can achieve a degradation efficiency of more than 85% for acetaldehyde in the fixed bed system. More importantly, the modified UiO-66 material in this invention also has a good degradation effect in the mobile phase system. In the mobile phase system, the modified UiO-66 material in this invention achieves a breakthrough in the efficiency of photocatalytic degradation of acetaldehyde compared with the traditional UiO-66 material. It is very suitable for application in the photocatalytic degradation of gaseous mobile phase acetaldehyde. This provides a new possibility for the treatment of acetaldehyde in mobile phase systems such as actual atmospheric environment and indoor environment. Attached Figure Description

[0021] Figure 1 The pore size distribution curves are shown for the modified UiO-66 materials prepared in Examples 1-3 of this invention and the UiO-66 material prepared in Comparative Example 1.

[0022] Figure 2 The images show the UV-Vis absorption spectra of the modified UiO-66 materials prepared in Examples 1-3 of this invention and the UiO-66 material prepared in Comparative Example 1.

[0023] Figure 3 The CO2-TPD curves of the modified UiO-66 materials prepared in Examples 1-3 of this invention and the UiO-66 material prepared in Comparative Example 1 are shown.

[0024] Figure 4 The diagram shows the contact angle results of the modified UiO-66 material prepared in Examples 1-3 of this invention and the UiO-66 material prepared in Comparative Example 1 with water.

[0025] Figure 5 The graph shows the adsorption results of acetaldehyde in the mobile phase system of the modified UiO-66 material prepared in Examples 1-3 of the present invention and the UiO-66 material prepared in Comparative Example 1.

[0026] Figure 6 The graphs show the degradation curves of acetaldehyde in the mobile phase system for the modified UiO-66 materials prepared in Examples 1-3 and Comparative Example 1. Figure 6 In the figure, the vertical axis represents the change in acetaldehyde concentration under illumination after the material reaches adsorption-desorption equilibrium and the light is turned on. C0 represents the initial concentration of acetaldehyde, and C represents the real-time concentration of acetaldehyde. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] The present invention provides a method for preparing a modified UiO-66 material (also referred to as a modified UiO-66 metal-organic framework material) in a first aspect, the method comprising the following steps:

[0029] (1) Add pure water to N,N-dimethylformamide (DMF) and mix evenly to obtain mixture A. Then add zirconium metal source and organic ligand to mixture A and mix evenly to obtain mixture B.

[0030] (2) The mixture B is subjected to a hydrothermal reaction to obtain a reaction solution;

[0031] (3) The reaction product is separated from the reaction solution and dried to obtain the modified UiO-66 material.

[0032] The method of this invention is simple and low-cost. For the first time in the synthesis of traditional UiO-66 materials, it introduces basic sites by adding pure water. After modification, UiO-66 has significantly increased basic sites and hydrophilicity, greatly increasing the adsorption of acidic gases (such as acetaldehyde). Through simple modification, this invention effectively regulates the morphology, acid-base sites, and hydrophilic properties of UiO-66 materials, significantly improving degradation efficiency. The resulting modified UiO-66 material is particularly suitable for the photocatalytic degradation of acidic gases. At the same time, the modification method of this invention does not significantly affect the band gap of the UiO-66 material itself. The modified UiO-66 material prepared in this invention, while containing certain defects, improves the proportion of mesopores, specific surface area, and surface properties, which is beneficial for gas adsorption and mass transfer. It increases the number of basic sites and hydrophilicity, particularly facilitating the adsorption of acetaldehyde (a Lewis acid, a polar gas). The adsorption performance for acetaldehyde is significantly increased, with the adsorption capacity in the mobile phase system increasing from 0.6 μmol / g before modification to over 159.1 μmol / g after modification. More importantly, the modified UiO-66 material in this invention also exhibits excellent degradation performance in the mobile phase system. The degradation efficiency of traditional UiO-66 material in the mobile phase system is essentially close to zero. Compared to traditional UiO-66 material, the modified UiO-66 material in this invention achieves a breakthrough in the photocatalytic degradation efficiency of acetaldehyde in the mobile phase system, making it highly suitable for application in the photocatalytic degradation of acetaldehyde in gaseous mobile phases. This provides a significant advantage for mobile phase applications in practical atmospheric and indoor environments. This invention offers a new possibility for acetaldehyde treatment. Furthermore, it discovers that only by introducing pure water into the synthesis of UiO-66 material can the proportion of mesopores and the specific surface area of ​​the UiO-66 material be significantly increased. This is beneficial for gas adsorption and mass transfer, increases the number of basic sites and hydrophilicity, and is particularly beneficial for acetaldehyde adsorption, greatly enhancing the adsorption performance of acetaldehyde and significantly improving the degradation efficiency of UiO-66 material for acetaldehyde. Adding pure water can also affect the crystallization rate and crystal nucleus growth rate of the product; samples with pure water have smaller crystal sizes and are more likely to form a gel state. This invention also finds that while adding other acids or quaternary ammonium salts during the synthesis of UiO-66 material can increase the specific surface area compared to traditional UiO-66 materials, it has virtually no effect on increasing the number of basic sites and hydrophilicity, and therefore does not significantly improve the efficiency of acetaldehyde degradation by UiO-66 material.

[0033] According to some preferred embodiments, the molar ratio of the pure water to the zirconium metal source is (3.5 to 40):1 (e.g., 3.5:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1 or 40:1), preferably (15 to 25):1.

[0034] This invention introduces different amounts of water into the conventional synthesis of UiO-66, causing the UiO-66 grain size to gradually decrease, gradually gel, increase specific surface area, increase alkaline sites, and increase hydrophilicity. This results in a breakthrough in the photodegradation efficiency of polar, acidic VOCs (acetaldehyde) in the mobile phase system, exceeding zero. Through a simple modification, the morphology and acid-base sites of UiO-66 are effectively controlled. More preferably, the molar ratio of pure water to zirconium metal source is (15-25):1, which is more conducive to obtaining the modified UiO-66 material with more alkaline sites, better hydrophilicity, higher specific surface area, better acetaldehyde adsorption, and better acetaldehyde degradation effect.

[0035] According to some preferred embodiments, the zirconium metal source is one or more of zirconium tetrachloride, zirconium nitrate, and zirconium sulfate, preferably zirconium tetrachloride (ZrCl4); and / or the organic ligand is terephthalic acid and / or 2-aminoterephthalic acid.

[0036] According to some preferred embodiments, the mass ratio of the zirconium metal source to the organic ligand is (0.3-0.4):(0.2-0.3), preferably, the molar ratio of the zirconium metal source to the organic ligand is 1:(0.98-1.05); and / or the volume ratio of the pure water to the N,N-dimethylformamide is (0.1-1):50 (e.g., 0.1:50, 0.2:50, 0.3:50, 0.4:50, 0.5:50, 0.6:50, 0.7:50, 0.8:50, 0.9:50 or 1:50).

[0037] According to some preferred embodiments, the temperature of the hydrothermal reaction is 100-160°C (e.g., 100°C, 110°C, 120°C, 130°C, 140°C, 150°C or 160°C), and the time of the hydrothermal reaction is 10-24h (e.g., 10, 12, 14, 16, 18, 20, 22 or 24h).

[0038] According to some preferred embodiments, in step (3): the reaction product is separated from the reaction solution by centrifugation and washing.

[0039] According to some preferred embodiments, in step (3): the drying is vacuum drying at 80-120°C for 6-10 hours.

[0040] According to some preferred embodiments, in step (3), after separating and drying the reaction product from the reaction solution, oxygen plasma treatment is performed to obtain the modified UiO-66 material; in this invention, preferably, the atmosphere of the oxygen plasma treatment is oxygen, the power of the oxygen plasma treatment is 30-50W, and the time of the oxygen plasma treatment is 30-300s (e.g., 30, 60, 90, 120, 150, 180, 210, 240, 270 or 300s).

[0041] In this invention, oxygen plasma treatment is preferred. This introduces oxygen-containing groups onto the surface of the modified UiO-66 material, which increases the material's alkaline sites and hydrophilicity, thereby enhancing its interaction with acidic pollutants such as acetaldehyde. This facilitates the contact between acetaldehyde molecules and the modified UiO-66 material surface, improving adsorption performance and degradation efficiency. Furthermore, oxygen plasma treatment can alter the chemical properties of the UiO-66 material surface, introduce active sites, regulate the material's pore structure and surface morphology, and improve its adsorption performance and catalytic activity. Moreover, this invention has undergone extensive innovation... Through creative experiments, suitable power and time for oxygen plasma treatment were obtained. The preferred oxygen plasma treatment power is 30-50W and the treatment time is 30-300s. This invention found that if the oxygen plasma treatment power is too low and / or the time is too short, the effect on further improving the performance of UiO-66 material is not obvious. If the oxygen plasma treatment power is too high and / or the time is too long, excessive oxygen plasma treatment will destroy the crystal structure of the modified UiO-66 material, leading to damage or collapse of the pore structure, thereby affecting its adsorption and catalytic performance.

[0042] According to some preferred embodiments, the modified UiO-66 material is a material for degrading acetaldehyde; the specific surface area of ​​the modified UiO-66 material is not less than 1000 m². 2 / g, preferably not less than 1200m 2 / g; the modified UiO-66 material adsorbs acetaldehyde in the mobile phase system at a rate of not less than 49 μmol / g, preferably not less than 150 μmol / g; and / or the contact angle between the modified UiO-66 material and water is not greater than 41°, preferably 20–25°.

[0043] According to some specific implementation methods, the modified UiO-66 material is prepared as follows:

[0044] Add pure water to N,N-dimethylformamide (DMF) and stir for 4–10 min to obtain a homogeneous mixture A. Then add zirconium tetrachloride and terephthalic acid to mixture A and stir for 1–3 h to obtain a homogeneous mixture B. Mixture B is placed in a reaction vessel (a reaction vessel with a polytetrafluoroethylene liner and a stainless steel liner) and hydrothermally reacted at 100–160°C for 10–24 hours. It is then cooled to room temperature and centrifuged and washed sequentially with N,N-dimethylformamide (DMF) and ethanol, for example, three times each with N,N-dimethylformamide (DMF) and ethanol. Finally, it is vacuum dried at 80–120°C for 6–10 hours. The present invention does not specify the rotational speed of the term "stirring," for example, it can be 600–700 r / min. The present invention uses a conventional reaction vessel for hydrothermal reactions, and the pressure inside the reaction vessel is not specifically limited, as this is conventional technology in the field. During the hydrothermal reaction, the pressure inside the reaction vessel increases, for example, by 0.3–1.5 MPa.

[0045] In a second aspect, the present invention provides a modified UiO-66 material prepared by the preparation method described in the first aspect of the present invention.

[0046] In a third aspect, the present invention provides the application of the modified UiO-66 material prepared by the preparation method described in the first aspect in the degradation of acetaldehyde.

[0047] According to some preferred embodiments, the modified UiO-66 material has an efficiency of not less than 85% in degrading acetaldehyde in a fixed-bed system; and / or the modified UiO-66 material has an efficiency of not less than 35% in degrading acetaldehyde in a mobile phase system.

[0048] It is worth noting that the "fixed bed system" and "mobile phase system" described in this invention are explained here. The fixed bed system can be understood as a reactor filled with particulate solid catalysts or solid reactants, forming a bed of a certain height. The gas to be degraded enters from one end of the reactor and flows out from the other end. The gas to be degraded can completely pass through the catalyst and flow through the gaps between the particles through the stationary fixed bed, thus realizing a heterogeneous reaction process. The "mobile phase system" described in this invention is actually a model simulating the contact between acetaldehyde and a sample coating (such as a sample coating for degrading acetaldehyde applied to the surface of a wall) in the atmospheric environment. Specifically, the formation of the "mobile phase system" in this invention can be as follows: a sample coating (a sample for degrading acetaldehyde) is placed in the reactor (reaction chamber). The coating does not contact the surrounding area of ​​the reactor. The gas (acetaldehyde) can flow through the gaps between the coating and the reactor and through the surface of the coating. This can simulate the contact model between acetaldehyde and the sample coating in the atmospheric environment, which is closer to the actual indoor environment. Compared with the fixed bed system, the "mobile phase system" in this invention has higher requirements for the ability of the sample (the sample used to degrade acetaldehyde) to capture and degrade acetaldehyde, and the reaction is more difficult. It is more difficult to efficiently absorb acetaldehyde from the mobile phase and then degrade it.

[0049] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0050] Example 1

[0051] 0.1 mL of pure water was added to 50 mL of N,N-dimethylformamide (DMF) and stirred for 5 min to obtain a homogeneous mixture A. Then, 0.35 g of zirconium tetrachloride and 0.25 g of terephthalic acid were added to mixture A and stirred for 2 h to obtain a homogeneous mixture B. Mixture B was placed in a reaction vessel and hydrothermally reacted at 120 °C for 12 h. After cooling to room temperature, the mixture was washed three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. Finally, it was vacuum dried at 100 °C for 8 h to obtain the modified UiO-66 material (denoted as U-1).

[0052] Example 2

[0053] 0.5 mL of pure water was added to 50 mL of N,N-dimethylformamide (DMF) and stirred for 5 min to obtain a homogeneous mixture A. Then, 0.35 g of zirconium tetrachloride and 0.25 g of terephthalic acid were added to mixture A and stirred for 2 h to obtain a homogeneous mixture B. Mixture B was placed in a reaction vessel and hydrothermally reacted at 120 °C for 12 h. After cooling to room temperature, the mixture was washed three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. Finally, it was vacuum dried at 100 °C for 8 h to obtain the modified UiO-66 material (denoted as U-2).

[0054] Example 3

[0055] 1.0 mL of pure water was added to 50 mL of N,N-dimethylformamide (DMF) and stirred for 5 min to obtain a homogeneous mixture A. Then, 0.35 g of zirconium tetrachloride and 0.25 g of terephthalic acid were added to mixture A and stirred for 2 h to obtain a homogeneous mixture B. Mixture B was placed in a reaction vessel and hydrothermally reacted at 120 °C for 12 h. After cooling to room temperature, the mixture was washed three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. Finally, it was vacuum dried at 100 °C for 8 h to obtain the modified UiO-66 material (denoted as U-3).

[0056] Example 4

[0057] 0.5 mL of pure water was added to 50 mL of N,N-dimethylformamide (DMF) and stirred for 5 min to obtain a homogeneous mixture A. Then, 0.35 g of zirconium tetrachloride and 0.25 g of terephthalic acid were added to mixture A and stirred for 2 h to obtain a homogeneous mixture B. Mixture B was placed in a reaction vessel and hydrothermally reacted at 120 °C for 12 h. After cooling to room temperature, the mixture was washed three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. It was then vacuum dried at 100 °C for 8 h, and finally subjected to oxygen plasma treatment at an oxygen atmosphere of 40 W for 120 s to obtain the modified UiO-66 material.

[0058] Example 5

[0059] 0.5 mL of pure water was added to 50 mL of N,N-dimethylformamide (DMF) and stirred for 5 min to obtain a homogeneous mixture A. Then, 0.35 g of zirconium tetrachloride and 0.25 g of terephthalic acid were added to mixture A and stirred for 2 h to obtain a homogeneous mixture B. Mixture B was placed in a reaction vessel and hydrothermally reacted at 120 °C for 12 h. After cooling to room temperature, the mixture was washed three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. It was then vacuum dried at 100 °C for 8 h, and finally subjected to oxygen plasma treatment at an oxygen atmosphere of 60 W for 480 s to obtain modified UiO-66 material.

[0060] Comparative Example 1

[0061] 0.35 g of zirconium tetrachloride and 0.25 g of terephthalic acid were added to 50 mL of N,N-dimethylformamide (DMF) and stirred for 2 h to obtain a homogeneous mixture. The mixture was placed in a reaction vessel and hydrothermally reacted at 120 °C for 12 h. After cooling to room temperature, the mixture was washed three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. Finally, it was vacuum dried at 100 °C for 8 h to obtain UiO-66 material (denoted as U-0).

[0062] The pore size distribution curves of the modified UiO-66 materials prepared in Examples 1-3 and the UiO-66 material prepared in Comparative Example 1 are shown below. Figure 1 As shown, from Figure 1 The results show that the modified UiO-66 material prepared by this invention has significantly more mesopores than the sample U-0 prepared without the introduction of pure water. The increased number of mesopores is beneficial for gas mass transfer within the catalyst. The UV-Vis absorption spectra of the modified UiO-66 materials prepared in Examples 1-3 of this invention and the UiO-66 material prepared in Comparative Example 1 are shown below. Figure 2 As shown, by Figure 2 The results show that the band gap of the modified UiO-66 material described in this invention is slightly increased compared to the UiO-66 material prepared in Comparative Example 1, which may be due to the introduction of ligand defects into the sample by the introduction of pure water; the CO2-TPD curves of the modified UiO-66 materials prepared in Examples 1-3 of this invention and the UiO-66 material prepared in Comparative Example 1 are shown below. Figure 3 As shown, this invention can characterize the types and quantities of basic sites in a sample using the CO2-TPD curve. Figure 3 The results show that the number of basic sites in the modified UiO-66 material has increased. Figure 3In the diagram, the horizontal axis represents the temperature at which CO2 is desorbed. Higher temperatures indicate stronger interaction between CO2 and the sample, representing strongly basic adsorption sites. Lower temperatures represent weakly basic or moderately strong adsorption sites. The peak area represents the amount of CO2 desorbed, reflecting the number of adsorption sites. The integrated area of ​​the CO2-TPD curve represents the number of basic sites; a larger integrated area indicates a greater number of basic sites. In this invention, the integrated area is the area below the CO2-TPD curve of the sample. The contact angle results of the modified UiO-66 materials prepared in Examples 1-3 and the UiO-66 material prepared in Comparative Example 1 with water are shown in the diagram. Figure 4 As shown, by Figure 4 It can be seen that the hydrophilicity of the modified UiO-66 material sample increases, indicating that the modified UiO-66 material has enhanced adsorption capacity for polar gases; the adsorption results of the modified UiO-66 materials prepared in Examples 1-3 of this invention and the UiO-66 material prepared in Comparative Example 1 for acetaldehyde in the mobile phase system are shown in the figure. Figure 5 As shown, by Figure 5 It can be seen that the modified UiO-66 material sample exhibits a significantly increased adsorption capacity for acetaldehyde, which is beneficial for the photodegradation of acetaldehyde. The degradation curves of the modified UiO-66 materials prepared in Examples 1-3 and Comparative Example 1 for acetaldehyde in the mobile phase system are shown below. Figure 6 As shown, from Figure 6 The results show that the modified UiO-66 material sample has a significantly improved photocatalytic degradation efficiency for acetaldehyde.

[0063] Comparative Example 2

[0064] Add 0.35 g zirconium tetrachloride and 0.25 g terephthalic acid to 50 mL of N,N-dimethylformamide (DMF) and stir for 2 h to obtain a homogeneous mixture A. Add 6 mL of acetic acid (purity ≥99.5%) to mixture A and stir for 1 h to obtain a homogeneous mixture B. Place mixture B in a reaction vessel and hydrothermally react at 120 °C for 12 h. Then cool to room temperature and wash three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. Finally, vacuum dry at 100 °C for 8 h to obtain UiO-66 material.

[0065] Comparative Example 3

[0066] Add 0.35 g zirconium tetrachloride, 0.25 g terephthalic acid, and 1.5 mL hydrochloric acid (containing 37% HCl by mass) to 50 mL of N,N-dimethylformamide (DMF), and stir for 2 h to obtain a homogeneous mixture. Place the mixture in a reaction vessel and hydrothermally react at 120 °C for 12 h. Then cool to room temperature, wash three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation, and finally vacuum dry at 100 °C for 8 h to obtain UiO-66 material.

[0067] Comparative Example 4

[0068] Add 0.35 g zirconium tetrachloride, 0.25 g terephthalic acid, and 1.5 mL hydrochloric acid (containing 37% HCl by mass) to 50 mL of N,N-dimethylformamide (DMF) and stir for 2 h to obtain a homogeneous mixture A. Then add 8 mL of deionized water containing citric acid and hexadecyltrimethylammonium bromide to mixture A and stir until homogeneous to obtain a homogeneous mixture B, wherein the molar ratio of zirconium tetrachloride, citric acid, and hexadecyltrimethylammonium bromide is 1:0.1:0.3. Place mixture B in a reaction vessel and hydrothermally react at 120 °C for 12 h. Then cool to room temperature and wash three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. Finally, vacuum dry at 100 °C for 8 h to obtain UiO-66 material.

[0069] Comparative Example 5

[0070] Add 0.35 g zirconium tetrachloride, 0.25 g terephthalic acid, and 1.5 mL hydrochloric acid (containing 37% HCl by mass) to 50 mL of N,N-dimethylformamide (DMF) and stir for 2 h to obtain a homogeneous mixture A. Then add 0.5 mL of pure water to mixture A and stir until homogeneous to obtain a homogeneous mixture B. Place mixture B in a reaction vessel and hydrothermally react at 120 °C for 12 h. Then cool to room temperature and wash three times each with N,N-dimethylformamide (DMF) and ethanol by centrifugation. Finally, vacuum dry at 100 °C for 8 h to obtain UiO-66 material.

[0071] The specific surface area, integral area of ​​the CO2-TPD curve, and hydrophilicity results of the modified UiO-66 materials prepared in each embodiment and the UiO-66 materials prepared in each comparative example are shown in Table 1 below.

[0072] Table 1

[0073]

[0074]

[0075] The degradation efficiency (corresponding to degradation time of 240 min) of the modified UiO-66 material prepared in each embodiment and the UiO-66 material prepared in each comparative example was measured in both fixed-bed and fluidized-bed systems, as shown in Table 2. The adsorption capacity of the modified UiO-66 material prepared in each embodiment and the UiO-66 material prepared in each comparative example for acetaldehyde was also measured in the fluidized-bed system, as shown in Table 2. It should be noted that the test conditions for the fluidized-bed system in this invention are as follows: 50 mg of modified UiO-66 material sample... After the modified UiO-66 material sample is evenly dispersed in ethanol, it is coated onto a glass plate and placed in a 500 mL chamber. Acetaldehyde with a concentration of 200 ppm is introduced at a flow rate of 20 mL / min. The fixed-bed system test conditions are as follows: the test is carried out in a quartz glass tube with an inner diameter of 6 mm and a length of 300 mm. The amount of modified UiO-66 material sample or UiO-66 material sample is 100 mg. Both ends are sealed with cotton. Acetaldehyde with a concentration of 200 ppm is introduced at a flow rate of 20 mL / min.

[0076] Table 2

[0077]

[0078]

[0079] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The application of a modified UiO-66 material in the adsorption and degradation of acetaldehyde, characterized in that, The preparation method of the modified UiO-66 material includes the following steps: (1) Add pure water to N,N-dimethylformamide and mix evenly to obtain mixture A. Then add zirconium metal source and organic ligand to mixture A and mix evenly to obtain mixture B. The molar ratio of pure water to zirconium metal source is (15~25):

1. The organic ligand is terephthalic acid. (2) The mixture B is subjected to a hydrothermal reaction to obtain a reaction solution; (3) Separate the reaction product from the reaction solution and dry it, and then perform oxygen plasma treatment to obtain modified UiO-66 material; the atmosphere of the oxygen plasma treatment is oxygen, the power of the oxygen plasma treatment is 30~50W, and the time of the oxygen plasma treatment is 30~300s.

2. The application according to claim 1, characterized in that: The zirconium metal source is one or more of zirconium tetrachloride, zirconium nitrate, and zirconium sulfate.

3. The application according to claim 1, characterized in that: The mass ratio of the zirconium metal source to the organic ligand is (0.3~0.4):(0.2~0.3); and / or The volume ratio of the pure water to the N,N-dimethylformamide is (0.1~1):

50.

4. The application according to claim 1, characterized in that: The hydrothermal reaction temperature is 100~160℃, and the hydrothermal reaction time is 10~24h.

5. The application according to claim 1, characterized in that, In step (3): The drying process involves vacuum drying at 80-120℃ for 6-10 hours.

6. The application according to claim 1, characterized in that: The specific surface area of ​​the modified UiO-66 material is not less than 1000 m². 2 / g.

7. The application according to claim 6, characterized in that: The specific surface area of ​​the modified UiO-66 material is not less than 1200 m². 2 / g.

8. The application according to claim 1, characterized in that: The modified UiO-66 material has an acetaldehyde degradation efficiency of not less than 85% in a fixed-bed system.

9. The application according to claim 1, characterized in that: The modified UiO-66 material has an adsorption capacity of acetaldehyde of not less than 150 μmol / g in the mobile phase system.

10. The application according to claim 1, characterized in that: The modified UiO-66 material has an efficiency of not less than 35% in degrading acetaldehyde in the mobile phase system.

11. The application according to claim 1, characterized in that: The modified UiO-66 material has a contact angle of 20~25° with water.

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