Amino-functionalized titanium-based nanopore material and preparation method thereof

Abstract

The invention discloses an amino-functionalized titanium-based nanopore material and a preparation method thereof, and belongs to the technical field of waste gas treatment.The preparation method comprises the steps that a titanium sheet is subjected to anodic oxidation twice to generate a chromium-doped titanium dioxide nanotube, and then amino-functionalized titanium MOF grows on the surface of the nanotube in situ through a solvothermal reaction; the preparation method comprises the following steps: firstly, preparing amino-functionalized titanium-based composite powder, synthesizing silicon dioxide nanospheres through a sol-gel method, carrying out surface fluorination on perfluorodecyltrimethoxysilane to obtain a super-hydrophobic layer, modifying the amino-functionalized titanium-based composite powder through a silane coupling agent KH550, and finally, loading the fluorinated silicon dioxide nanospheres on the surfaces of the composite microspheres through electrostatic adsorption to obtain the super-hydrophobic coating. The amino-functionalized titanium-based nanopore material is obtained; the high adsorption capacity, wide-spectrum adsorption selectivity, good photocatalytic performance and good stability of the nanopore material are realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waste gas treatment, and particularly relates to an amino-functionalized titanium-based nanoporous material and a preparation method thereof. BACKGROUND

[0002] Nanoporous materials refer to porous materials with pore diameters in the nanometer scale range, and the pore size is generally between 1 nanometer and 100 nanometers. Nanoporous materials have the characteristics of super large specific surface area, adjustable pore size, good selectivity, fast transmission, and have wide application prospects in the fields of adsorption, separation, catalysis and the like.

[0003] Titanium-based nanoporous materials are titanium-based materials with porous structures. In order to solve the problems of insufficient surface chemical activity, poor adsorption selectivity and low catalytic efficiency of traditional titanium-based materials, and to meet the demand for multifunctional materials in the fields of environmental governance and energy conversion, amino groups are introduced to enable the material to have stronger molecular recognition ability, chemical adsorption activity and adjustable surface properties, while retaining the advantages of high stability and nanoporous structure of titanium-based materials, thus the amino-functionalized titanium-based nanoporous material appears.

[0004] Chinese patent application with publication number CN 112934201A discloses a composite waste gas adsorption material and a preparation method thereof. First, a rigid polymer ligand is obtained by organic synthesis with isophthalic acid as a starting material. Then, an acrylic acid monomer is grafted on nanocellulose whiskers with potassium persulfate as an initiator to obtain a biomass ligand. The rigid polymer ligand, the biomass ligand and a zinc salt solution are dissolved in DMF, and then the mixture is transferred to an autoclave for sealing reaction. After cooling and washing, a MOF material with double ligands is obtained. The MOF material is finally obtained by high-temperature heat treatment, and the composite waste gas adsorption material has excellent adsorption effect on waste gas.

[0005] However, when the composite waste gas adsorption material is used to treat humid waste gas, the zinc-based coordination bond in the material is prone to hydrolysis in a humid environment, which causes the collapse of the metal organic framework skeleton structure, significantly reduces the specific surface area and porosity of the material, and leads to the decline of the adsorption effect and the shortening of the service life of the material, thereby increasing the use cost. SUMMARY

[0006] The purpose of the present application is to improve the poor applicability of nanoporous materials in humid and multi-component industrial waste gas environments, and to provide an amino-functionalized titanium-based nanoporous material and a preparation method thereof.

[0007] The application generates chromium-doped titanium dioxide nanotubes by twice anodic oxidation of titanium sheets, and then in-situ grows amino-functionalized titanium MOF on the surface of the nanotubes through a solvothermal reaction; silica nanospheres are synthesized by a sol-gel method, and an ultrahydrophobic layer is obtained by surface fluorination of perfluorodecyltrimethoxysilane, while the amino-functionalized titanium-based composite powder is modified by silane coupling agent KH550, and finally the fluorinated silica nanospheres are loaded on the surface of the composite microspheres by electrostatic adsorption to obtain the amino-functionalized titanium-based nanoporous material. The nanoporous material has good effects in adsorption capacity, moisture resistance and cycle stability.

[0008] The object of the application can be achieved by the following technical solutions. A preparation method of an amino-functionalized titanium-based nanoporous material, comprising the following steps: Step one: generate chromium-doped titanium dioxide nanotubes on the surface of titanium sheets by twice anodic oxidation of the titanium sheets to obtain chromium-doped titanium dioxide nanotube powder; then perform a solvothermal reaction on the titanium dioxide nanotube powder with an organic ligand and a titanium source to in-situ grow amino-functionalized titanium MOF, thereby obtaining amino-functionalized titanium-based composite powder.

[0009] Step two: prepare silica nanospheres under catalysis of ammonia by using tetraethyl orthosilicate as a silicon source, and perform surface fluorination modification to obtain fluorinated silica nanospheres; perform silanization treatment on the amino-functionalized titanium-based composite powder to obtain composite microspheres, disperse the fluorinated silica nanospheres into a nanoparticle liquid, immerse the composite microspheres in the nanoparticle liquid, perform electrostatic adsorption, filtration, and drying to obtain the amino-functionalized titanium-based nanoporous material.

[0010] Further, the chromium-doped titanium dioxide nanotube powder is prepared by the following steps: Ultrasonically clean titanium sheets with acetone, ethanol and deionized water for 20-30 min, transfer the titanium sheets to an electrolytic cell, add 0.3wt% ammonium fluoride electrolyte, use a platinum plate as a counter electrode, perform anodic oxidation at 30-40V for 1-2h, gently rinse the wet titanium sheets with deionized water for 10-20 min to obtain wet titanium sheets with nanotubes; add chromium nitrate and 0.3wt% ammonium fluoride electrolyte into a beaker, stir for 10 min, introduce nitrogen for 80-90 min, transfer the wet titanium sheets with nanotubes to the electrolytic cell, perform anodic oxidation at 20-30V for 30-40 min, take out, ultrasonically clean at 300-400W for 15-20 min, wash the powder with deionized water and ethanol for 3-5 times, vacuum dry at 60℃ for 2-3h, transfer to a muffle furnace, heat at a rate of 5℃ / min to 450-500℃, keep the temperature for 2-3h to obtain the chromium-doped titanium dioxide nanotube powder.

[0011] Further, the size of the titanium sheet is 3cm×3cm×1cm, and the dosage ratio of the titanium sheet to the 0.3wt% ammonium fluoride electrolyte is 20-25 sheets to 4-6L.

[0012] Further, the use amount ratio of the chromium nitrate and the 0.3wt% ammonium fluoride electrolyte is 28.8-38.4g:0.5-0.8L.

[0013] Further, the amino-functionalized titanium-based composite powder is prepared by the following steps: 2-amino terephthalic acid, hydrochloric acid and N,N-dimethyl formamide are added into a reaction kettle, stirred for 10-20min, chromium-doped titanium dioxide nanotubes and titanium tetrachloride are added, and reaction is carried out at 120-150℃ for 20-24h, then the mixture is cooled, filtered, the filter cake is washed with ethanol and deionized water for 3-5 times, and vacuum drying is carried out at 60℃ for 8-12h to obtain the amino-functionalized titanium-based composite powder.

[0014] Further, the use amount ratio of 2-amino terephthalic acid, hydrochloric acid, N,N-dimethyl formamide, chromium-doped titanium dioxide nanotubes and titanium tetrachloride is 0.3-0.6g:0.1-0.2mL:50-100mL:0.5-1g:0.1-0.2g.

[0015] Further, the fluorinated silicon dioxide nanospheres are prepared by the following steps: Ammonia water and ethanol are added into a reaction kettle, constant temperature is maintained at 50-60℃ for 5-10min, tetraethyl orthosilicate is slowly added, stirring is carried out at 400-500rpm for 20-30min, condensation reflux is carried out for 2-3h, perfluorodecyltrimethoxysilane is added, and reaction is continued for 2-3h, then the mixture is cooled to room temperature, centrifugal filtration is carried out, washing is carried out with anhydrous ethanol for 3-5 times, and vacuum drying is carried out at 60℃ for 2-3h to obtain the fluorinated silicon dioxide nanospheres.

[0016] Further, the volume ratio of ammonia water, ethanol, tetraethyl orthosilicate and perfluorodecyltrimethoxysilane is 8-10:200-250:6-8:0.2-0.3.

[0017] Further, the amino-functionalized titanium-based nanoporous material is prepared by the following steps: Amino-functionalized titanium-based composite powder, ethanol and silane coupling agent KH550 are added into a reaction kettle, ultrasonic treatment is carried out for 30-40min, stirring is carried out at 50-60℃ for 3-4h, and vacuum drying is carried out to obtain composite microspheres; fluorinated silicon dioxide nanospheres and anhydrous ethanol are added into a reaction kettle, ultrasonic treatment is carried out for 20-30min to obtain a nanoparticle liquid; the composite microspheres are added into the nanoparticle liquid, stirring is carried out at 30-40℃ for 20-30min, filtration is carried out, and drying is carried out at 80℃ for 2-3h to obtain the amino-functionalized titanium-based nanoporous material.

[0018] Further, the ratio of the amount of use of the amino-functionalized titanium-based composite powder, ethanol and silane coupling agent KH550 is 0.5-1 g: 250-500 mL: 2.5-5 mL.

[0019] Further, the ratio of the amount of use of the fluorinated silica nanosphere and anhydrous ethanol is 4-8 g: 200-400 mL. Further, the ratio of the amount of use of the composite microspheres and nanoparticle liquid is 0.5-1 g: 200-400 mL.

[0020] Advantages of the present application: 1. The present application provides photocatalytic activity and enhances electrical conductivity by doping chromium titanium dioxide nanotube powder, introduces high specific surface area, microporous structure and abundant amino adsorption sites on the surface of the amino-functionalized titanium-based MOF, and loads perfluorodecyltrimethoxysilane modified silica nanospheres on the outer layer to construct a super-hydrophobic surface and mesoporous structure. The amino MOF and fluorinated silica cooperate to realize complementary adsorption of hydrophilic, polar pollutants and hydrophobic pollutants, and the doping of chromium dioxide core and the adsorption interface cooperates to enable the adsorbed organic pollutants to be in-situ catalytically degraded under visible light, realizing self-cleaning regeneration, and the KH550 molecular bridge stably connects the hydrophilic core (titanium dioxide / titanium MOF) and the hydrophobic shell, ensuring the effective integration of the multifunctional interface. At the same time, the components together construct a multi-stage pore, micropore-mesopore-macropore, which optimizes the material transport efficiency and total adsorption capacity, and the synergistic protection of the fluorinated silica shell further enhances the selectivity and stability of the material, ultimately making the nanoporous material have high adsorption capacity, wide spectrum adsorption selectivity, good photocatalytic performance and good stability.

[0021] 2. The chromium-doped titanium dioxide nanotube powder in the present application significantly narrows the band gap of titanium dioxide by chromium doping, endows the material with excellent visible light response and photocatalytic activity, improves the carrier separation efficiency, greatly enhances the redox ability, and the one-dimensional nanotube structure provides an efficient material transport channel and a high specific surface area loading platform. The introduction of chromium ions and the synergistic effect of high-temperature calcination process strengthen the structural stability and electrical conductivity of the material. These characteristics not only make it a high-efficiency photocatalyst, but also lay a structural foundation for the growth and compounding of the subsequent amino MOF functional layer, provide synergistic catalytic activity, and support the stable loading of the hydrophobic shell. 3、The amino-functionalized titanium-based composite powder in the application realizes a substantial increase in the targeted adsorption capacity of heavy metal ions, acid gases and other pollutants by the super-high specific surface area of the amino MOF and the rich amino groups through the chemical bonding of the chromium-doped titanium dioxide nanotube and the amino MOF heterostructure, the built-in electron transport channel promotes the efficient separation of photo-generated carriers at the interface between titanium dioxide and the MOF, drives the in-situ degradation of adsorbed pollutants under visible light, forms a dynamic cycle of "adsorption-photocatalytic self-cleaning", and the rigid MOF skeleton coating significantly enhances the structural stability and acid erosion resistance of the nanotube, providing high activity and high stability for subsequent hydrophobic functionalization.

[0022] 4、The fluorinated silicon dioxide nanosphere in the application forms a superhydrophobic layer by the modification of perfluorodecyltrimethoxysilane, selectively adsorbs oil and organic pollutants, and simultaneously efficiently blocks the invasion of water molecules, avoids the occupation of the amino sites in the core by water molecules, and cooperatively constructs a multi-stage mass transfer channel by the through mesopores formed by the nanosphere stacking and the micropores / macropores in the core, greatly improves the diffusion rate of macromolecular pollutants. Finally, the rigid silicon dioxide skeleton coating the core significantly enhances the mechanical strength and chemical stability of the composite material, and forms a stable connection with the amino-functionalized core through the silane coupling agent KH550, realizes the molecular-level cooperation of the hydrophobic-hydrophilic interface, and finally provides the core capabilities of targeted oil-water separation, long-term moisture resistance and structure protection for the material. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the application will be described clearly and completely below in conjunction with the embodiments in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0024] Embodiment 1: A preparation method of an amino-functionalized titanium-based nanoporous material, comprising the following steps: S1: 20 titanium sheets were ultrasonically cleaned with acetone, ethanol and deionized water for 20 min, transferred to an electrolytic cell, 4 L of 0.3 wt% ammonium fluoride electrolyte was added, a platinum plate was used as the counter electrode, anodic oxidation was carried out at 30 V for 1 h, and the wet titanium sheet with nanotubes was obtained by gently washing with deionized water for 10 min; 28.8 g of chromium nitrate and 0.5 L of 0.3 wt% ammonium fluoride electrolyte were added to a beaker, stirred for 10 min, and nitrogen was introduced for 80 min; the wet titanium sheet with nanotubes was transferred to the electrolytic cell and anodized at 20 V for 30 min; the powder was washed with deionized water and ethanol for 3 times, and vacuum dried at 60°C for 2 h; transferred to a muffle furnace, heated to 450°C at a rate of 5°C / min, and kept for 2 h to obtain chromium-doped titanium dioxide nanotube powder.

[0025] By two-step anodic oxidation method, pure titanium dioxide nanotubes are formed in the first step, and doping is achieved in the second step in an electrolyte containing chromium ions, combined with heat treatment to achieve crystallization and doping stabilization; the nanotube structure provides high specific surface area and directional pores to enhance the reaction activity, and chromium doping can reduce the band gap to expand the visible light response range and inhibit electron-hole recombination, so the obtained powder has high catalytic activity and chemical stability.

[0026] S2: 0.3 g of 2-amino terephthalic acid, 0.1 mL of hydrochloric acid and 50 mL of N,N-dimethylformamide were added to a reaction kettle, stirred for 10 min, 0.5 g of chromium-doped titanium dioxide nanotubes and 0.1 g of titanium tetrachloride were added, and reacted at 120°C for 20 h; cooled, filtered, and the filter cake was washed with ethanol and deionized water for 3 times, and vacuum dried at 60°C for 8 h to obtain amino-functionalized titanium-based composite powder.

[0027] The composite of metal organic framework and inorganic nanomaterial is prepared by solvothermal synthesis method, and titanium-based metal organic framework is grown in situ on the surface of chromium-doped titanium dioxide nanotubes as a substrate to form a nanocomposite with a hierarchical pore structure; it has super strong adsorption capacity and photoelectric catalytic performance, and also improves the structural stability of MOF.

[0028] S3: 8 mL of ammonia water and 200 mL of ethanol were added to a reaction kettle, heated at 50°C for 5 min, 6 mL of tetraethyl orthosilicate was slowly added, stirred at 400 rpm for 20 min, and refluxed for 2 h; 0.2 mL of perfluorodecyltrimethoxysilane was added and the reaction was continued for 2 h; cooled to room temperature, centrifuged and filtered, washed with anhydrous ethanol for 3 times, and vacuum dried at 60°C for 2 h to obtain fluorinated silica nanospheres.

[0029] By sol-gel method, ammonia catalytic tetraethyl orthosilicate hydrolysis and polycondensation in alcohol aqueous solution, monodisperse silica nanospheres are formed, then modified by perfluorodecyltrimethoxysilane on the surface, covalently grafting long-chain perfluoro group on the surface, making the nanospheres super-hydrophobic, super-oleophobic, low surface energy and high chemical stability; fluorinated layer significantly improves the anti-pollution, self-cleaning and interfacial compatibility.

[0030] S4: 0.5 g of amino-functionalized titanium-based composite powder, 250 mL of ethanol and 2.5 mL of silane coupling agent KH550 are added into a reaction kettle, ultrasonic for 30 min, stirring at 50℃ for 3h, vacuum drying, to obtain composite microspheres; 4 g of fluorinated silica nanospheres and 200 mL of anhydrous ethanol are added into a reaction kettle, ultrasonic for 20 min, to obtain a nanoparticle liquid; 0.5 g of composite microspheres is added into 200 mL of nanoparticle liquid, stirring at 30℃ for 20 min, filtering, drying at 80℃ for 2h, to obtain amino-functionalized titanium-based nanoporous material.

[0031] By electrostatic adsorption, the negatively charged fluorinated silica nanospheres are quickly coated on the surface of the positively charged amino-functionalized titanium-based composite powder, forming a core-shell structure; while retaining the photocatalytic activity and large specific surface area of titanium-based materials, the whole is super-biphobic, realizing self-cleaning and anti-pollution.

[0032] Example 2: A preparation method of an amino-functionalized titanium-based nanoporous material, comprising the following steps: S1: 23 titanium sheets are ultrasonically cleaned with acetone, ethanol and deionized water for 25 min, transferred to an electrolytic cell, 5L of 0.3wt% ammonium fluoride electrolyte is added, a platinum plate is used as a counter electrode, anodic oxidation is carried out at 35V for 1.5h, the wet titanium sheet with nanotubes is gently washed with deionized water for 15 min, to obtain a wet titanium sheet with nanotubes; 33.6g of chromium nitrate and 0.65L of 0.3wt% ammonium fluoride electrolyte are added into a beaker, stirred for 10 min, nitrogen is introduced for 85 min, the wet titanium sheet with nanotubes is transferred into an electrolytic cell, anodic oxidation is carried out at 25V for 35 min, taken out, ultrasonic is carried out at 350W for 17.5 min, the powder is washed with deionized water and ethanol for 4 times, vacuum drying is carried out at 60℃ for 2.5h, transferred into a muffle furnace, heated to 475℃ at a rate of 5℃ / min, and kept for 2.5h, to obtain chromium-doped titanium dioxide nanotube powder.

[0033] S2: 0.45g of 2-amino terephthalic acid, 0.15mL of hydrochloric acid and 75mL of N,N-dimethylformamide are added into a reaction kettle, stirred for 15 min, 0.75g of chromium-doped titanium dioxide nanotube and 0.15g of titanium tetrachloride are added, reacted at 135℃ for 22h, cooled, filtered, the filter cake is washed with ethanol and deionized water for 4 times, vacuum drying is carried out at 60℃ for 10h, to obtain amino-functionalized titanium-based composite powder.

[0034] S3: 9 mL of ammonia and 225 mL of ethanol were added to the reaction kettle, and constant temperature was maintained at 55°C for 7.5 min, 7 mL of tetraethyl orthosilicate was slowly added, stirring at 450 rpm for 25 min, condensing reflux for 2.5 h, adding 0.25 mL of perfluorodecyl trimethoxysilane, continuing to react for 2.5 h, cooling to room temperature, centrifugal filtration, washing with anhydrous ethanol 4 times, vacuum drying at 60°C for 2.5 h, to obtain fluorinated silica nanospheres.

[0035] S4: 0.75 g of amino-functionalized titanium-based composite powder, 375 mL of ethanol and 3.75 mL of silane coupling agent KH550 were added to the reaction kettle, ultrasonic for 35 min, stirring at 55°C for 3.5 h, vacuum drying to obtain composite microspheres; 6 g of fluorinated silica nanospheres and 300 mL of anhydrous ethanol were added to the reaction kettle, ultrasonic for 25 min to obtain a nanoparticle liquid; 0.75 g of composite microspheres was added to 300 mL of nanoparticle liquid, stirring at 35°C for 25 min, filtering, drying at 80°C for 2.5 h to obtain amino-functionalized titanium-based nanoporous material.

[0036] Example 3: A preparation method of an amino-functionalized titanium-based nanoporous material, comprising the following steps: S1: 25 titanium sheets were ultrasonically cleaned with acetone, ethanol and deionized water for 30 min, transferred to an electrolytic cell, 6 L of 0.3 wt% ammonium fluoride electrolyte was added, a platinum plate was used as a counter electrode, anodic oxidation was carried out at 40 V for 2 h, and the wet titanium sheet with nanotubes was gently washed with deionized water for 20 min to obtain a wet titanium sheet with nanotubes; 38.4 g of chromium nitrate and 0.8 L of 0.3 wt% ammonium fluoride electrolyte were added to a beaker, stirred for 10 min, and nitrogen was introduced for 90 min. The wet titanium sheet with nanotubes was transferred to the electrolytic cell and anodized at 30 V for 40 min. The powder was washed with deionized water and ethanol 5 times, vacuum dried at 60°C for 3 h, transferred to a muffle furnace, heated to 500°C at a rate of 5°C / min, and kept for 3 h to obtain chromium-doped titanium dioxide nanotube powder.

[0037] S2: 0.6 g of 2-amino terephthalic acid, 0.2 mL of hydrochloric acid and 100 mL of N,N-dimethylformamide were added to the reaction kettle, stirred for 20 min, 1 g of chromium-doped titanium dioxide nanotube and 0.2 g of titanium tetrachloride were added, and reacted at 150°C for 24 h. After cooling, the filter cake was washed with ethanol and deionized water 5 times, and vacuum dried at 60°C for 12 h to obtain an amino-functionalized titanium-based composite powder.

[0038] S3: 10 mL of ammonia and 250 mL of ethanol were added into a reaction kettle, and the reaction kettle was kept at 60℃ for 10 min, 8 mL of tetraethyl orthosilicate was slowly added, and stirring was performed at 500 rpm for 30 min, and condensation reflux was performed for 3 h, 0.3 mL of perfluorodecyltrimethoxysilane was added, and the reaction was continued for 3 h, and the reaction was cooled to room temperature, centrifugal filtration was performed, and the product was washed with anhydrous ethanol for 5 times, and vacuum drying was performed at 60℃ for 3 h to obtain fluorinated silica nanospheres.

[0039] S4: 1 g of the amino-functionalized titanium-based composite powder, 500 mL of ethanol and 5 mL of silane coupling agent KH550 were added into a reaction kettle, and ultrasonic treatment was performed for 40 min, and stirring was performed at 60℃ for 4 h, and vacuum drying was performed to obtain composite microspheres; 8 g of the fluorinated silica nanospheres and 400 mL of anhydrous ethanol were added into a reaction kettle, and ultrasonic treatment was performed for 30 min to obtain a nanoparticle liquid; 1 g of the composite microspheres was added into 400 mL of the nanoparticle liquid, and stirring was performed at 40℃ for 30 min, and filtration was performed, and drying was performed at 80℃ for 3 h to obtain the amino-functionalized titanium-based nanoporous material.

[0040] In the formula, the size of the titanium sheet is 3 cm x 3 cm x 1 cm; the electrolytic cell for the first anodic oxidation is a rectangular tank with a size of 15 cm x 20 cm x 10 cm, and the electrolytic cell for the second anodic oxidation is a beaker.

[0041] The raw materials used in the examples 1-3 of the present application are commercially available, such as the titanium sheet purchased from Beijing Ruili Gaosi Technology Co., Ltd. (BJRC); 2-amino terephthalic acid purchased from Shanghai Hongzhuang Chemical Technology Co., Ltd. (Hongzhuang); and perfluorodecyltrimethoxysilane purchased from Shandong Jinsengtai Chemical Co., Ltd. (Jinsengtai).

[0042] Comparative Example 1: The difference from Example 1 is that no chromium nitrate is added in step S1, and only the first anodic oxidation is performed, and the second anodic oxidation is not performed, and the remaining steps remain unchanged, and the nanoporous material is prepared.

[0043] Comparative Example 2: The difference from Example 1 is that no titanium tetrachloride is added in step S2, and the remaining steps remain unchanged, and the nanoporous material is prepared.

[0044] Comparative Example 3: The difference from Example 1 is that the step S3 is not performed, and the remaining steps remain unchanged, and the nanoporous material is prepared.

[0045] The nanoporous materials prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 were subjected to adsorption treatment of water-containing volatile organic gas under a high humidity environment with a relative humidity of 80%, the same amount of Example 1-3 and Comparative Example was subjected to adsorption treatment under the same conditions, the adsorption temperature was 25°C, the initial concentration of volatile organic gas was maintained at 100ppm, the gas flow was 1L / min, a portable volatile organic analyzer (GC-FID Model 8807) was used to detect the concentration of toluene gas, and the adsorption capacity was calculated; the hydrophobic performance test was carried out according to the national standard GB / T 9706.1, the contact angle data was recorded; the regeneration experiment was tested according to the conventional nitrogen desorption and ultraviolet light irradiation, and the performance test was carried out according to the method of re-adsorption, and the results are shown in Table 1: Table 1: Performance test results of a kind of amino-functionalized titanium-based nanoporous material Item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Toluene adsorption capacity mg / g 245.6 237.1 220.9 150.3 148.2 198.3 Benzene adsorption capacity mg / g 186.3 175.2 170.1 122.3 114.7 148.7 M-xylene adsorption capacity mg / g 236.4 228.7 218.3 111.8 123.4 184.6 Contact angle ° 162.2 160.4 158.5 148.2 145.7 50.3 Regeneration rate % 95.9 92.7 90.5 85.2 78.7 52.3 As can be seen from Table 1, the performance of the nanoporous materials prepared in Example 1-Example 3 is significantly better than that of the comparative example. In the "adsorption-hydrophobic-regeneration" system constructed by the triple structure, the chromium-doped titanium dioxide nanotube has a high specific surface area mesoporous skeleton supporting the amino titanium MOF, specifically captures benzene series, and the toluene adsorption effect is good. The fluorinated silica nanosphere surface forms a super-hydrophobic layer, blocks the water molecules in the high humidity environment, reduces the desorption amount, and the chromium-doped titanium dioxide photocatalytic degradation of the residual material improves the cyclic regeneration rate.

[0046] The xylene adsorption capacity in Comparative Example 1 decreased significantly, which may be due to the lack of ordered chromium-doped titanium dioxide nanotube mesoporous channels, resulting in the inability of large xylene molecules with kinetic diameters to diffuse to the internal active sites efficiently. At the same time, in a high humidity environment, disordered channels are more likely to form a water film to block, further hindering mass transfer of large molecules, resulting in a much higher decrease in adsorption capacity than benzene and toluene.

[0047] In Comparative Example 2, the toluene adsorption capacity and benzene adsorption capacity decreased significantly, which may be due to the lack of titanium tetrachloride, resulting in the inability to form amino-functionalized MOF, the lack of π-π stacking of MOF, the loss of strong charge transfer between amino and toluene methyl groups, the greater loss of toluene due to electronic effect, and the partial dependence of benzene on residual physical adsorption. The essence is that the complete lack of chemical adsorption sites leads to a significant decrease in toluene adsorption capacity and benzene adsorption capacity.

[0048] In Comparative Example 3, the contact angle and regeneration rate decreased significantly, which may be due to the lack of the super-hydrophobic protective layer provided by the fluorinated silica nanosphere, the hydrophilic surface being occupied by water molecules, forming a hydrogen bond network with volatile organic compounds, greatly increasing the desorption energy, water molecules penetrating causing the hydrolysis of amino titanium MOF and the dissolution of chromium-doped titanium dioxide, leading to the collapse of the channels, the accumulation of pollution, and the blockage of the channels by carbonized residues of polar pollutants. The essence is that the lack of hydrophobic barrier leads to water erosion leading to material failure.

[0049] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptations will occur to those skilled in the art without departing from the spirit and scope of the present application.

Claims

1. A method for preparing an amino-functionalized titanium-based nanoporous material, characterized in that: The steps include: Step 1: A titanium sheet is anodized twice to generate chromium-doped titanium dioxide nanotubes on the surface of the titanium sheet to obtain chromium-doped titanium dioxide nanotube powder; then, a solvothermal reaction is carried out with an organic ligand and a titanium source to in situ grow amino-functionalized titanium MOF to obtain amino-functionalized titanium-based composite powder; Step 2: Using tetraethyl orthosilicate as a silicon source, silica nanospheres are prepared under ammonia catalysis, and surface fluorination modification is performed to obtain fluorinated silica nanospheres; amino-functionalized titanium-based composite powder is silanized to obtain composite microspheres, and then the fluorinated silica nanospheres are dispersed into nanoparticle liquid, and the composite microspheres are immersed in the nanoparticle liquid, electrostatic adsorption is performed, filtration is performed, and drying is performed to obtain amino-functionalized titanium-based nanoporous materials.

2. The method for preparing an amino-functionalized titanium-based nanoporous material according to claim 1, characterized in that: The chromium-doped titanium dioxide nanotube powder is prepared by the following steps: The titanium sheet was ultrasonically cleaned with acetone, ethanol and deionized water for 20-30 minutes, transferred to an electrolytic cell, 0.3wt% ammonium fluoride electrolyte was added, and anodization was performed at 30-40V for 1-2 hours using a platinum plate as a counter electrode. The sheet was gently rinsed with deionized water for 10-20 minutes to obtain a wet titanium sheet with nanotubes. Chromium nitrate and 0.3wt% ammonium fluoride electrolyte were added to a beaker, stirred for 10 minutes, and nitrogen was introduced for 80-90 minutes. The wet titanium sheet with nanotubes was transferred to an electrolytic cell, anodized at 20-30V for 30-40 minutes, taken out, and ultrasonicated at 300-400W for 15-20 minutes. The powder was washed with deionized water and ethanol 3-5 times, vacuum dried at 60°C for 2-3 hours, transferred to a muffle furnace, heated to 450-500°C at a rate of 5°C / min, and kept warm for 2-3 hours to obtain chromium-doped titanium dioxide nanotube powder.

3. The method for preparing an amino-functionalized titanium-based nanoporous material according to claim 2, characterized in that: The size of the titanium sheet is 3cm×3cm×1cm, and the usage ratio of the titanium sheet to the 0.3wt% ammonium fluoride electrolyte is 20-25 sheets: 4-6L; the usage ratio of the chromium nitrate to the 0.3wt% ammonium fluoride electrolyte is 28.8-38.4g: 0.5-0.8L.

4. The method for preparing an amino-functionalized titanium-based nanoporous material according to claim 1, characterized in that: The amino-functionalized titanium-based composite powder is prepared by the following steps: 2-Aminoterephthalic acid, hydrochloric acid and N,N-dimethylformamide are added to a reaction kettle and stirred for 10-20 minutes. Chromium-doped titanium dioxide nanotubes and titanium tetrachloride are added and reacted at 120-150°C for 20-24 hours. The mixture is cooled and filtered. The filter cake is washed with ethanol and deionized water for 3-5 times and vacuum dried at 60°C for 8-12 hours to obtain an amino-functionalized titanium-based composite powder.

5. The method for preparing an amino-functionalized titanium-based nanoporous material according to claim 4, characterized in that: The usage ratio of the 2-aminoterephthalic acid, hydrochloric acid, N,N-dimethylformamide, chromium-doped titanium dioxide nanotubes and titanium tetrachloride is 0.3-0.6 g: 0.1-0.2 mL: 50-100 mL: 0.5-1 g: 0.1-0.2 g.

6. The method for preparing an amino-functionalized titanium-based nanoporous material according to claim 1, characterized in that: The fluorinated silica nanospheres are prepared by the following steps: Add ammonia water and ethanol to a reaction kettle, maintain the temperature at 50-60°C for 5-10 minutes, slowly add tetraethyl orthosilicate, stir at 400-500 rpm for 20-30 minutes, condense and reflux for 2-3 hours, add perfluorodecyltrimethoxysilane, continue to react for 2-3 hours, cool to room temperature, centrifuge and filter, wash with anhydrous ethanol 3-5 times, and vacuum dry at 60°C for 2-3 hours to obtain fluorinated silica nanospheres.

7. The method for preparing an amino-functionalized titanium-based nanoporous material according to claim 6, characterized in that: The volume ratio of the ammonia water, ethanol, tetraethyl orthosilicate and perfluorodecyltrimethoxysilane is 8-10:200-250:6-8:0.2-0.

3.

8. The method for preparing an amino-functionalized titanium-based nanoporous material according to claim 1, characterized in that: The amino-functionalized titanium-based nanoporous material is prepared by the following steps: Add amino-functionalized titanium-based composite powder, ethanol, and silane coupling agent KH550 into a reactor, ultrasonicate for 30-40 minutes, stir at 50-60°C for 3-4 hours, and vacuum dry to obtain composite microspheres; add fluorinated silica nanospheres and anhydrous ethanol into a reactor, ultrasonicate for 20-30 minutes to obtain a nanoparticle solution; The composite microspheres are added to the nanoparticle solution, stirred at 30-40° C. for 20-30 minutes, filtered, and dried at 80° C. for 2-3 hours to obtain an amino-functionalized titanium-based nanoporous material.

9. The method for preparing an amino-functionalized titanium-based nanoporous material according to claim 8, characterized in that: The usage ratio of the amino-functionalized titanium-based composite powder, ethanol and silane coupling agent KH550 is 0.5-1g:250-500mL:2.5-5mL; the usage ratio of the fluorinated silica nanospheres and anhydrous ethanol is 4-8g:200-400mL; and the usage ratio of the composite microspheres and nanoparticle liquid is 0.5-1g:200-400mL.

10. An amino-functionalized titanium-based nanoporous material, characterized in that: The material is prepared by the method for preparing an amino-functionalized titanium-based nanoporous material according to any one of claims 1 to 9.