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1.
A robust and highly water stable series of UiO-66-drived MOFs including UiO-66-NH2, glycidyl methacrylate functionalized UiO-66-NH2 (UiO-66-GMA) and ethylenediamine functionalized UiO-66-NH2 (UiO-66-EDA) were synthesized solvothermally and studied their adsorption performances toward two anti-cancer drugs, methotrexate (MTX) and curcumin (CUR) in the case of overdose. It was found that functionalizing the surface of UiO-66-NH2 nanoparticles with different functional groups remarkably changes the adsorption capacity and the ideal adsorption selectivity of MTX over CUR. Particularly, the UiO-66-EDA exhibited the highest adsorption capacities for both drugs, 540.78 and 423.85 mg/g for MTX and CUR, respectively, because of the strong interaction between drug molecules and adsorbent via hydrogen bonding due to the existence of different polar functional groups. The kinetics of drugs adsorption was investigated by three well-known kinetic models, which the output indicates that the adsorption of both drugs onto the synthesized MOFs follow the pseudo-second-order model. Moreover, it was found that the equilibrium adsorption results were well fitted with the Langmuir isotherm models, revealing that the adsorption of both drugs onto the synthesized MOFs is a monolayer adsorption process. Further investigation illustrated that the synthesized MOFs could be easily activated and reused after four successive adsorption–desorption cycles. The output of the present work is of main important for biomedical and environmental applications of MOFs as an outstanding adsorbent for adsorption removal of hazardous drugs from contaminated aqueous solutions.  相似文献   

2.
Composites of metal-organic frameworks and carbon materials have been suggested to be effective materials for the decomposition of chemical warfare agents. In this study, we synthesized UiO-66-NH2/zeolite-templated carbon (ZTC) composites for the adsorption and decomposition of the nerve agents sarin and soman. UiO-66-NH2/ZTC composites with good dispersion were prepared via a solvothermal method. Characterization studies showed that the composites had higher specific surface areas than pristine UiO-66-NH2, with broad pore size distributions centered at 1–2 nm. Owing to their porous nature, the UiO-66-NH2/ZTC composites could adsorb more water at 80% relative humidity. Among the UiO-66-NH2/ZTC composites, U0.8Z0.2 showed the best degradation performance. Characterization and gas adsorption studies revealed that beta-ZTC in U0.8Z0.2 provided additional adsorption and degradation sites for nerve agents. Among the investigated materials, including the pristine materials, U0.8Z0.2 also exhibited the best protection performance against the nerve agents. These results demonstrate that U0.8Z0.2 has the optimal composition for exploiting the degradation performance of pristine UiO-66-NH2 and the adsorption performance of pristine beta-ZTC.  相似文献   

3.
UiO-66 amine functionalized was synthesized by solvothermal method. Post-synthetic modification of UiO-66-NH2 with piperazine, a known promoter to enhance the chemisorption rate of CO2 uptake, was carried out and analyzed to understand its crystalline structure, morphology and porous structure. Results show that piperazine is an effective agent for enhancing the capacity of absorption of CO2. This porous product exhibits an improved CO2 uptake at pressures up to 3000 kPa via physisorption and chemisorption mechanisms. The CH4 adsorption and desorption isotherms on UiO-66, UiO-66-NH2 and pip-UiO-66-NH2 at temperature of 298.15 K and pressures ranging from 0 to 5000 kPa were carried out. IAS theory for a mixture of 0.05 bar CO2, 0.85 bar CH4 and 0.1 bar other gas revealed a selectivity factor of 19.09 for CO2/CH4 from pip-UiO-66-NH2. Results show that these materials are effective adsorbents for CO2 and CH4 uptakes.  相似文献   

4.
In this work, mesoporous silica (SBA‐15‐NH2) was used as an efficient adsorbent for extraction of chlordiazepoxide from different samples based on dispersive nanomaterial‐ultrasound assisted microextraction followed by high‐performance liquid chromatography. The prepared sorbent was characterized by fourier transform infrared spectroscopy, scanning electron microscopy, low‐angle X‐ray diffraction, thermal analysis, and N2 adsorption‐desorption surface area measurement. Several variables affecting the extraction efficiency of the chlordiazepoxide, including the amounts of adsorbent, time of adsorption, pH and volume of desorption solvent were optimized by central composite design combined with desirability function. The values of variables were set as 10 mg of SBA‐15‐NH2, 15 min adsorption time, pH = 7.3 and 1 mL methanol. The linear response (0.998) was obtained in the range of 0.006–10 µgmL?1 with detection limit 0.0014 µg/mL and extraction recovery was in the range of 91–96% with relative standard deviation < 6%.  相似文献   

5.
In this study, a strategy that can result in the polyaniline (PANI) solely confined within the nanopores of a metal–organic framework (MOF) without forming obvious bulk PANI between MOF crystals is developed. A water-stable zirconium-based MOF, UiO-66-NH2, is selected as the MOF material. The polymerization of aniline is initiated in the acidic suspension of UiO-66-NH2 nanocrystals in the presence of excess poly(sodium 4-styrenesulfonate) (PSS). Since the pore size of UiO-66-NH2 is too small to enable the insertion of the bulky PSS, the quick formation of pore-confined solid PANI and the slower formation of well dispersed PANI:PSS occur within the MOF crystals and in the bulk solution, respectively. By taking advantage of the resulting homogeneous PANI:PSS polymer solution, the bulk PANI:PSS can be removed from the PANI/UiO-66-NH2 solid by successive washing the sample with fresh acidic solutions through centrifugation. As this is the first time reporting the PANI solely confined in the pores of a MOF, as a demonstration, the obtained PANI/UiO-66-NH2 composite material is applied as the electrode material for supercapacitors. The PANI/UiO-66-NH2 thin films exhibit a pseudocapacitive electrochemical characteristic, and their resulting electrochemical activity and charge-storage capacities are remarkably higher than those of the bulk PANI thin films.  相似文献   

6.
以三氟乙酰基和五氟丙酰基为修饰官能团,通过合成后修饰(PSM)的方法对金属-有机骨架(MOFs)改性,得到疏水骨架材料(UiO-66-F1和UiO-66-F2)。2个骨架材料均显示出亲油性,这说明它们是油性溶剂潜在的吸附材料。修饰后MOFs材料的结晶性、稳定性和多孔性较UiO-66-NH2仅有微小降低。UiO-66-F1和UiO-66-F2的Brunauer-Emmett-Teller(BET)比表面积分别为810和610 m2·g-1。骨架材料因其合适的孔大小和疏水微环境,更容易吸附水中的有机污染物。此外,改性后材料对多种有机溶剂的吸附量显著提升,在经过10次的循环吸附后吸附量没有明显降低,具有出色的循环稳定性。  相似文献   

7.
The photocatalytic reduction of toxic Cr(VI), to green Cr(III) by visible light, is highly required. Metal-organic frameworks have been waged more and more devotion in the field of environmental remediation. Diversification along with functionalization is still thought-provoking and crucial for the progress of metal-organic framework (MOF)-based high activity materials. Herein, a succession of UiO-66-NH2@ZnIn2S4 composites with varying amount of UiO-66-NH2 is prepared by the facile solvothermal technique. Synergetic effect for Cr(VI) reduction is assessed under the influence of visible light (λ > 420 nm). UiO-66-NH2 octahedron is detained by ZnIn2S4 nanoflakes. The obvious enhancement in activity is observed which is credited to the well-suited energy band construction and close interaction between the interface of ZnIn2S4 and UiO-66-NH2, which leads to effective transfer and separation of photogenerated carriers. Synergistic effect could be evidently understood from the PL and UV -spectroscopy, after molding into heterostructure of UiO-66-NH2@ZnIn2S4. In addition, UiO-66-NH2@ZnIn2S4 composites exhibited good stability in photocatalytic reduction. Consequently, this UiO-66-NH2 constructed composite has high potential in the field of environmental remediation.  相似文献   

8.
The thin film photocatalysts were prepared from solvothermal UiO-66-NH2 and sol-gel perovskite LaFeO3 by a dip-coating technique. The properties of obtained catalysts were investigated by the methods of Brunauer-Emmett-Teller adsorption, XRD, SEM, FT-IR, TGA, and UV-vis spectroscopies. The results proved that the thin film of the thickness of 4.2 and 4.7 µm was successfully prepared from micro-mesoporous UiO-66-NH2 and LaFeO3 nanocrystals. Possessing small crystals (9-35 nm) and the band gap energy of 2.83 and 1.92 eV, respectively, UiO-66-NH2 and LaFeO3 are shown to be a highly active visible-light photocatalyst for photodegradation of p-xylene-contained gas. The kinetics of photocatalytic degradation of p-xylene under combined illumination of ultraviolet and visible lights over obtained UiO-66-NH2 and LaFeO3 thin films were carried out in a gradientless flow circulating system at room temperature and atmospheric pressure. The results showed that the Langmuir-Hinshelwood kinetic model was successfully applied to correlate the obtained data. The kinetics of the reaction on both catalysts were found to be written by the fractional equation, describing the dependence of the reaction rate on the concentration of p-xylene, oxygen molecules, dissociative adsorbed water vapor, the photon flux, and the inhibition of CO2 product. It implies that the reaction occurred at high surface coverages, molecular p-xylene, and oxygen participated in the reaction in the form of surface molecular; water—in the forms of OH and H+. Although there is a general kinetic equation for reaction on various catalysts, the different affinities of the catalysts with the compounds present in the reaction create the kinetic feature of the reaction on each catalyst. Because of the high affinity of catalysts with water vapor, the given reactant increased the rate of p-xylene photocatalytic degradation at low concentration but inhibited it in the high concentration region. The adsorption affinity of LaFeO3 to oxygen is higher compared to UiO-66-NH2; then, there was an optimum concentration of oxygen in the photodegradation of p-xylene on the former, whereas in the latter monotonically increasing relationship was found.  相似文献   

9.
The hydrolysis of nerve agents is of primary concern due to the severe toxicity of these agents. Using a MOF-based catalyst (UiO-66), we have previously demonstrated that the hydrolysis can occur with relatively fast half-lives of 50 minutes. However, these rates are still prohibitively slow to be efficiently utilized for some practical applications (e.g., decontamination wipes used to clean exposed clothing/skin/vehicles). We thus turned our attention to derivatives of UiO-66 in order to probe the importance of functional groups on the hydrolysis rate. Three UiO-66 derivatives were explored; UiO-66-NO2 and UiO-66-(OH)2 showed little to no change in hydrolysis rate. However, UiO-66-NH2 showed a 20 fold increase in hydrolysis rate over the parent UiO-66 MOF. Half-lives of 1 minute were observed with this MOF. In order to probe the role of the amino moiety, we turned our attention to UiO-67, UiO-67-NMe2 and UiO-67-NH2. In these MOFs, the amino moiety is in close proximity to the zirconium node. We observed that UiO-67-NH2 is a faster catalyst than UiO-67 and UiO-67-NMe2. We conclude that the role of the amino moiety is to act as a proton-transfer agent during the catalytic cycle and not to hydrogen bond or to form a phosphorane intermediate.  相似文献   

10.

Bi2WO6/UiO-66-NH2 photocatalysts were fabricated through solvothermal method using acetic acid as template. The photocatalytic performance of as-fabricated composites was highly improved under simulated visible light due to the addition of UiO-66-NH2. The structural and chemical properties of the composites were characterized through FTIR, XRD, XPS, SEM, BET, UV–vis DRS and PL. After 90 min of visible light irradiation, the RhB at an initial concentration of 10 mg·L?1 in the solution was degraded by 99.4% due to the addition of 10 mg of the composite. There was no significant decrease in the photocatalytic activity even after four rounds of cycles. The free radical capture experiments indicate that the photogenerated holes (h+) were the main active sites. The possible photocatalytic degradation mechanism was proposed as the specific surface area of the composite was enlarged due to the uniform distribution of UiO-66-NH2 on the surface of Bi2WO6. The electron–hole pairs recombination rate was decreased due to the photogenerated electrons (e?) on the CB of Bi2WO6 which can be rapidly transferred to the CB of UiO-66-NH2 and the photogenerated holes of UiO-66-NH2 transferred to the VB of Bi2WO6. Meanwhile, the RhB was directly oxidized to H2O and CO2 by h+ to achieve the purification effect.

  相似文献   

11.
A UiO-66-NCS MOF was formed by postsynthetic modification of UiO-66-NH2. The UiO-66-NCS MOFs displays a circa 20-fold increase in activity against the chemical warfare agent simulant dimethyl-4-nitrophenyl phosphate (DMNP) compared to UiO-66-NH2, making it the most active MOF materials using a validated high-throughput screening. The −NCS functional groups provide reactive handles for postsynthetic polymerization of the MOFs into functional materials. These MOFs can be tethered to amine-terminated polypropylene polymers (Jeffamines) through a facile room-temperature synthesis with no byproducts. The MOFs are then crosslinked into a MOF–polythiourea (MOF–PTU) composite material, maintaining the catalytic properties of the MOF and the flexibility of the polymer. This MOF–PTU hybrid material was spray-coated onto Nyco textile fibers, displaying excellent adhesion to the fiber surface. The spray-coated fibers were screened for the degradation of DMNP and showed durable catalytic reactivity.  相似文献   

12.
UiO-66-NH2-IM, a fluorescent metal-organic framework (MOF), was synthesized by post-synthetic modification of UiO-66-NH2 with 2-imidazole carboxaldehyde via a Schiff base reaction. It was examined using various characterization techniques (PXRD, FTIR, NMR, SEM, TGA, UV-Vis DRS, and photoluminescence spectroscopy). The emissive feature of UiO-66-NH2-IM was utilized to detect volatile organic compounds (VOCs), metal ions, and anions, such as acetone, Fe3+, and carbonate (CO32−). Acetone turns off the high luminescence of UiO-66-NH2-IM in DMSO, with the limit of detection (LOD) being 3.6 ppm. Similarly, Fe3+ in an aqueous medium is detected at LOD=0.67 μM (0.04 ppm) via quenching. On the contrary, CO32− in an aqueous medium significantly enhances the luminescence of UiO-66-NH2-IM, which is detected with extremely high sensitivity (LOD=1.16 μM, i. e., 0.07 ppm). Large Stern-Volmer constant, Ksv, and low LOD values indicate excellent sensitivity of the post-synthetic MOF. Experimental data supported by density functional theory (DFT) calculations discern photo-induced electron transfer (PET), resonance energy transfer (RET), inner filter effect (IFE), or proton abstraction as putative sensing mechanisms. NMR and computational studies propose a proton abstraction mechanism for luminescence enhancement with CO32−. Moreover, the optical behavior of the post-synthetic material toward analytes is recyclable.  相似文献   

13.
Precisely tuning the nuclearity of supported metal nanoclusters is pivotal for designing more superior catalytic systems, but it remains practically challenging. By utilising the chemical and molecular specificity of UiO-66-NH2 (a Zr-based metal–organic framework), we report the controlled synthesis of supported bi- and trinuclear Cu-oxo nanoclusters on the Zr6O4 nodal centres of UiO-66-NH2. We revealed the interplay between the surface structures of the active sites, adsorption configurations, catalytic reactivities and associated reaction energetics of structurally related Cu-based ‘single atoms’ and bi- and trinuclear species over our model photocatalytic formic acid reforming reaction. This work will offer practical insight that fills the critical knowledge gap in the design and engineering of new-generation atomic and nanocluster catalysts. The precise control of the structure and surface sensitivities is important as it can effectively lead to more reactive and selective catalytic systems. The supported bi- and trinuclear Cu-oxo nanoclusters exhibit notably different catalytic properties compared with the mononuclear ‘Cu1’ analogue, which provides critical insight for the engineering of more superior catalytic systems.

The controlled synthesis of novel bi- and trinuclear Cu-oxo nanoclusters supported on UiO-66-NH2 that show notably different catalytic properties in the photocatalytic formic acid decomposition reaction is reported.  相似文献   

14.
朱竞  钟顺  孙林  戴勇 《无机化学学报》2023,39(8):1510-1518
将光响应分子甲基螺吡喃SP-CH3引入UiO-66的非极性孔笼中,构筑吸附活性位可光控调节的光响应吸附剂。SP-CH3功能化的吸附剂完好保留了载体UiO-66的骨架和孔道结构。以阴离子染料甲基橙为探针,研究了吸附剂在不同光照条件下的吸附和解吸性能。结果表明,经紫外光照后,吸附剂对甲基橙的吸附量为41.99 mg·g-1,相较于可见光照后样品的吸附量提升57.56%,吸附作用增强;经可见光照后,甲基橙的脱附量为81.6%。本策略通过光照刺激改变UiO-66孔笼中SP-CH3的构型及表面电荷性质,即对吸附活性位进行光控调节,在不同光照条件下实现对吸附质的高效吸附和有效脱附。  相似文献   

15.
Exploring new catalytic strategies for achieving efficient CO2 hydrogenation under mild conditions is of great significance for environmental remediation. Herein, a composite photocatalyst Zr-based MOF encapsulated plasmonic AuPt alloy nanoparticles (AuPt@UiO-66-NH2) was successfully constructed for the efficient photothermal catalysis of CO2 hydrogenation. Under light irradiation at 150 °C, AuPt@UiO-66-NH2 achieved a CO production rate of 1451 μmol gmetal−1 h−1 with 91 % selectivity, which far exceeded those obtained by Au@Pt@UiO-66-NH2 with Pt shell on Au (599 μmol gmetal−1 h−1) and Au@UiO-66-NH2 (218 μmol gmetal−1 h−1). The outstanding performances of AuPt@UiO-66-NH2 were attributed to the synergetic effect originating from the plasmonic metal Au, doped active metal Pt, and encapsulation structure of UiO-66-NH2 shell. This work provides a new way for photothermal catalysis of CO2 and a reference for the design of high-performance plasmonic catalysts.  相似文献   

16.
In this work, adsorption properties of the UiO-66 metal–organic framework were investigated, with particular emphasis on the influence of structural defects. A series of UiO-66 samples were synthesized and characterized using a wide range of experimental techniques. Type I adsorption isotherms for low-temperature adsorption of N2 and Ar showed that micropore volume and specific surface area significantly increase with the number of defects. Adsorption of hexane isomers in UiO-66 was studied by means of quasi-equilibrated temperature-programmed desorption and adsorption (QE-TPDA) experimental and Monte Carlo simulation techniques. QE-TPDA profiles revealed that only defect-free UiO-66 exhibits distinct two adsorption states. This technique also yielded high-quality adsorption isobars that were successfully recreated using Grand-Canonical Monte Carlo molecular simulations, which, however, required refinement of the existing force fields. The calculations demonstrated the detailed mechanism of adsorption and separation of hexane isomers in the UiO-66 structure. The preferred tetrahedral cages provide suitable voids for bulky molecules, which is the reason for unusual “reverse” selectivity of UiO-66 towards di-branched alkanes. Interconnection of the tetrahedral cavities due to missing organic linkers greatly reduces the selectivity of the defected material.  相似文献   

17.
Extraction and determination of three flavonoids (morin, quercetin, and kaempferol) were performed by dispersive magnetic solid phase extraction based on mixed hemi/ad‐micelles and high‐performance liquid chromatography with UV detection. The Fe3O4/SiO2 nanoparticles were synthesized and characterized by X‐ray diffraction, FTIR, scanning electron microscopy, and thermogravimetric analysis. Fe3O4/SiO2 nanoparticles coated with mixed hemi/ad‐micelles cetyltrimethyl ammonium bromide was applied as a sorbent and used for extraction of flavonoids. Effective parameters on the extraction recovery such as amount of magnetic nano particles, volume of cetyltrimethyl ammonium bromide solution with specific concentration, pH of sample solution, adsorption equilibrium time, volume of desorption solvent, and desorption times were evaluated and optimized using fractional factorial design and central composite design. Under the optimum condition limit of detection and linearity were 0.83, 2.7–500.0 for morin, 0.18, 0.7–500.0 for quercetin and, 0.37, 1.3–500.0 µg/L for kaempferol. The extraction recovery with relative standard deviation were 97.88, 1.94 for morin, 95.77, 0.80 for quercetin, and 93.35, 1.45 for kaempferol. The proposed method was applied for simultaneous extraction and determination of flavonoids in several fruit juices and vegetable samples.  相似文献   

18.
《中国化学快报》2022,33(7):3577-3580
In this work, we proposed a new U(VI) removal strategy combining adsorption and photocatalytic reduction by the PMo12/UiO-66 heterojunctions. The PMo12 has been encapsulated in the cavities of UiO-66 by a one-step hydrothermal method, and the PMo12/UiO-66 exhibited high adsorption capacity and photocatalytic activity. The maximal theoretical sorption capacity of U(VI) on 15% PMo12/UiO-66 reached 225.36 mg/g and the photoreduction rate of 15% PMo12/UiO-66 is about thirty times as much as UiO-66. Under the light irradiation, the photogenerated electrons rapidly transport from UiO-66 to PMo12, and the photo-generated electrons could efficiently reduce the pre-enriched U(VI) to U(IV). This work provides new insights into remediation of the radioactive environment.  相似文献   

19.
UiO-66 and chitosan/UiO-66 composites were successfully synthesized by varying the mass addition of chitosan which were 0%, 2.5%, 5%, 10%, and 20% of the mass of UiO-66, denoted as UiO-66, Cs(2.5)/UiO-66, Cs(5)/UiO-66, Cs(10)/UiO-66, and Cs(20)/UiO-66, respectively. UiO-66 was modified with chitosan using the impregnation process. The X-ray diffraction patterns of the synthesized materials showed characteristic peaks at 2θ of 7.25° and 8.39°, which matched to that of the reported UiO-66. In addition, the Fourier transform infrared spectroscopy spectra of the materials showed absorption bands at the same wavenumber as UiO-66 and chitosan previously reported. The surface morphology of UiO-66 observed from scanning electron microscopy images was in the form of agglomerated small cube particles, where the smaller particles were observed for Cs(10)/UiO-66. From the N2 adsorption isotherms, it was found that the Brunauer-Emmett-Teller surface areas of UiO-66, Cs(5)/UiO-66, and Cs(10)/UiO-66 materials were 825.7 m2/g, 835.4 m2/g, and 882.2 m2/g, respectively. The results of the study on adsorption of methyl orange in aqueous solutions showed that Cs(5)/UiO-66 had the highest adsorption capacity of 370.37 mg/g and followed the pseudo–second-order adsorption kinetic with a Langmuir isotherm model.  相似文献   

20.
将光响应分子甲基螺吡喃SP-CH3引入UiO-66的非极性孔笼中,构筑吸附活性位可光控调节的光响应吸附剂。SP-CH3功能化的吸附剂完好保留了载体UiO-66的骨架和孔道结构。以阴离子染料甲基橙为探针,研究了吸附剂在不同光照条件下的吸附和解吸性能。结果表明,经紫外光照后,吸附剂对甲基橙的吸附量为41.99 mg·g-1,相较于可见光照后样品的吸附量提升57.56%,吸附作用增强;经可见光照后,甲基橙的脱附量为81.6%。本策略通过光照刺激改变UiO-66孔笼中SP-CH3的构型及表面电荷性质,即对吸附活性位进行光控调节,在不同光照条件下实现对吸附质的高效吸附和有效脱附。  相似文献   

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