"Shake 'n Bake" Route to Functionalized Zr-UiO-66 Metal-Organic Frameworks.
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ABSTRACT:
SUBMITTER: D'Amato R
PROVIDER: S-EPMC8456408 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:We present a dielectric spectroscopy study of dipolar dynamics in the hydrated UiO-66(Zr) type metal-organic frameworks (MOFs) functionalized with -NH2 and -F groups. Experiments are performed in a broad temperature and frequency ranges allowing us to probe several dipolar relaxations. For both samples at temperature below 220 K, we observe confined supercooled water dynamics, which can be described by the Arrhenius law. At slightly higher temperature, a second less pronounced dipolar relaxation is identified, and its origin is discussed. At even higher temperature, the dielectric permittivity exhibits anomalous increase with increasing temperature due to the proton conductivity. Upon further heating, the permittivity shows a sudden decrease indicating a reversible removal of water molecules. Measurements of the dehydrated samples reveal absence of all three dipolar processes.
| S-EPMC7221552 | biostudies-literature
Project description:This work reports on the fabrication, optimization and characterization of ultrathin films containing submicrometer particles (sMPs) of the hydrophilic and water stable UiO-66-COOH(Zr) metal organic framework (MOF). MOF particles of ≈200 nm have been synthesized and assembled at the air-water interface by the Langmuir-Blodgett technique. The use of different solvents, mixtures of solvents and surfactants has been investigated in order to improve the stability of MOF dispersions and reduce particle aggregation. The compact MOF/surfactant films containing 10 wt % octadecylphoshonic acid (ODP) have been deposited on substrates of different nature by Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) methods, showing that the presence of even only one MOF/ODP monolayer can increase the water contact angle of highly hydrophilic substrates such as mica or glass up to 120°. These films were characterized by scanning electron microscopy, grazing incidence X-ray diffraction, Fourier transform infrared spectroscopy and atomic force microscopy, revealing the formation of a continuous film where ODP molecules adopt an almost vertical position and cover MOF particles. Moreover, the presence of MOF particles significantly enhances the surface roughness and allows ultrathin, hydrophobic coverage to be obtained. Finally, it has been shown that the crystallinity and the porosity of the MOF remains almost unaltered in MOF/ODP films.
| S-EPMC6423563 | biostudies-literature
Project description:UiO-66-NH2, a zirconium-based functional metal-organic framework (MOF), was postsynthetically modified via Schiff base reaction between aldehyde groups in glutaraldehyde and amino groups in UiO-66-NH2 and CO2-preabsorbed polyethyleneimine (PEI). The resulting PEI-modified MOFs, abbreviated as PEIC@UiO, were characterized with 1H NMR, Fourier transform infrared, powder X-ray diffraction, Brunauer-Emmett-Teller, scanning electron microscopy, and thermogravimetric analysis and evaluated as CO2 adsorbents. In comparison with pristine UiO-66-NH2, the PEIC@UiO adsorbents have reduced specific surface area (7-150 m2/g) but maintained the same crystal structure. Particularly, the PEIC96@UiO adsorbent exhibited significantly improved CO2/N2 adsorption selectivity (48 vs 25) and higher CO2 adsorption capacity (3.2 vs 2.7 mmol/g). The adsorbent also displayed moderate desorption energy (68 kJ/mol CO2), superior moisture endurance, and recyclability, which are very desirable for practical applications.
| S-EPMC6648867 | biostudies-literature
Project description:The removal of uremic toxins from patients with acute kidney injury is a key issue in improving the quality of life for people requiring peritoneal dialysis. The currently utilized method for the removal of uremic toxins from the human organism is hemodialysis, performed on semipermeable membranes where the uremic toxins, along with small molecules, are separated from proteins and blood cells. In this study, we describe a mixed-linker modulated synthesis of zirconium-based metal-organic frameworks for efficient removal of uremic toxins. We determined that the efficient adsorption of uremic toxins is achieved by optimizing the ratio between -amino functionalization of the UiO-66 structure with 75% of -NH2 groups within organic linker structure. The maximum adsorption of hippuric acid and 3-indoloacetic acid was achieved by UiO-66-NH2 (75%) and by UiO-66-NH2 (75%) 12.5% HCl prepared by modulated synthesis. Furthermore, UiO-66-NH2 (75%) almost completely adsorbs 3-indoloacetic acid bound to bovine serum albumin, which was used as a model protein to which uremic toxins bind in the human body. The high adsorption capacity was confirmed in recyclability test, which showed almost 80% removal of 3-indoloacetic acid after the third adsorption cycle. Furthermore, in vitro cytotoxicity tests as well as hemolytic activity assay have proven that the UiO-66-based materials can be considered as potentially safe for hemodialytic purposes in living organisms.
| S-EPMC8485328 | biostudies-literature
Project description:The mixed-ligand strategy was selected as an approach to tailor a metal-organic framework (MOF) with microextraction purposes. The strategy led to the synthesis of up to twelve UiO-66-based MOFs with different amounts of functionalized terephthalate ligands (H-bdc), including nitro (-NO2) and amino (-NH2) groups (NO2-bdc and NH2-bdc, respectively). Increases of 25% in ligands were used in each case, and different pore environments were thus obtained in the resulting crystals. Characterization of MOFs includes powder X-ray diffraction, infrared spectroscopy, and elemental analysis. The obtained MOFs with different degrees and natures of functionalization were tested as sorbents in a dispersive miniaturized solid-phase extraction (D-µSPE) method in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD), to evaluate the influence of mixed functionalization of the MOF on the analytical performance of the entire microextraction method. Eight organic pollutants of different natures were studied, using a concentration level of 5 µg· L-1 to mimic contaminated waters. Target pollutants included carbamazepine, 4-cumylphenol, benzophenone-3, 4-tert-octylphenol, 4-octylphenol, chrysene, indeno(1,2,3-cd)pyrene, and triclosan, as representatives of drugs, phenols, polycyclic aromatic hydrocarbons, and disinfectants. Structurally, they differ in size and some of them present polar groups able to form H-bond interactions, either as donors (-NH2) or acceptors (-NO2), permitting us to evaluate possible interactions between MOF pore functionalities and analytes' groups. As a result, extraction efficiencies can reach values of up to 60%, despite employing a microextraction approach, with four main trends of behavior being observed, depending on the analyte and the MOF.
| S-EPMC6832283 | biostudies-literature
Project description:The variables examined were initial fluoride concentration, ZIF-8 and Uio-66 dosage, pH, and contact time. The residual concentration of fluoride was measured by a spectrophotometer. According to BET, the specific surface area of the ZIF-8 and Uio-66 was 1050?m2/g and 800?m2/g, respectively. Total pore volume and average pore diameter of the ZIF-8 and Uio-66 were 0.57?cm3/g, 0.45?cm3/g and 4.5?nm, 3.2?nm, respectively. The best pH for fluoride adsorption was neutral conditions. By increasing the ZIF-8 and Uio-66 dose, the fluoride uptake increased at first, but then decreased. Also, the maximum adsorption for ZIF-8 and Uio-66 was observed in adsorbent dose 0.2 and 0.6?g/L, respectively. The best model for describing kinetic and isotherms of fluoride adsorption were the pseudo-second-order model and Langmuir isotherm model, respectively. Based on the Langmuir model, the adsorption capacity of fluoride by ZIF-8 and Uio-66 was reported to be 25?mg/g and 20?mg/g, respectively.
| S-EPMC6134192 | biostudies-literature
Project description:Gas separation membranes are one of the lowest energy technologies available for the separation of carbon dioxide from flue gas. Key to handling the immense scale of this separation is maximised membrane permeability at sufficient selectivity for CO2 over N2. For the first time it is revealed that metals can be post-synthetically exchanged in MOFs to drastically enhance gas transport performance in membranes. Ti-exchanged UiO-66 MOFs have been found to triple the gas permeability without a loss in selectivity due to several effects that include increased affinity for CO2 and stronger interactions between the polymer matrix and the Ti-MOFs. As a result, it is also shown that MOFs optimized in previous works for batch-wise adsorption applications can be applied to membranes, which have lower demands on material quantities. These membranes exhibit exceptional CO2 permeability enhancement of as much as 153% when compared to the non-exchanged UiO-66 mixed-matrix controls, which places them well above the Robeson upper bound at just a 5 wt.% loading. The fact that maximum permeability enhancement occurs at such low loadings, significantly less than the optimum for other MMMs, is a major advantage in large-scale application due to the more attainable quantities of MOF needed.
| S-EPMC4296298 | biostudies-literature
Project description:The synthesis of ultrasmall UiO-66 nanoparticles (NPs) with an average size of 25 nm, determined by X-ray powder diffraction and electron microscopies analysis, is reported. The NPs were stabilized in water by dialyzing the NP from the DMF used for the synthesis. DLS measurements confirmed the presence of particles of 100 nm, which are spherical aggregates of smaller particles of 20⁻30 nm size. The NP have a BET surface area of 700 m²/g with an external surface area of 300 m²/g. UiO-66_N (UiO-66 nanoparticles) were loaded with acridine orange as fluorescent probe. UV-vis spectroscopy analysis revealed no acridine loss after 48 h of agitation in simulated body fluid. The biocompatibility of UiO-66_N was evaluated in human glioblastoma (GBM) cell line U251, the most malignant (IV grade of WHO classification) among brain tumors. In U251 cells, UiO-66_N are inert since they do not alter the cell cycle, the viability, migration properties, and the expression of kinases involved in cancer cell growth. The internalization process was evident after a few hours of incubation. After 24 h, UiO-66_N@Acr (UiO-66_N loaded with acridine orange) were detectable around the nuclei of the cells. These data suggest that small UiO-66 are biocompatible NP and could represent a potential carrier for drug delivery in glioblastoma therapies.
| S-EPMC6267206 | biostudies-literature
Project description:The use of large amounts of deleterious solvents in the synthesis of metal-organic frameworks (MOFs) is one of the important factors limiting their application in industry. Herein, we present a detailed study of the synthesis of UiO-66, which was conducted with hydrobromic (HBr) acid as a modulator for the first time, at a high concentration of precursor solution (ZrCl4 and H2BDC, both 0.2 mol L-1). Powder crystals with atypical cuboctahedron structure were obtained which indicated that the HBr acid modulator played roles by competitive coordination and deprotonation modulation, thereby controlling the processes of nucleation and crystal growth. The properties of the obtained materials were systematically characterized and compared with those of materials synthesized with hydrofluoric (HF) acid and hydrochloric (HCl) acid modulators. Despite the high concentration of defectivity, the UiO-66 material synthesized with the HBr acid additive has the characteristics of larger specific surface area, excellent thermal stability and higher porosity in the structure. Besides that, the present protocol has the advantages of high reaction mass efficiency (RME), and feasibility of scalable synthesis, providing a facile and sustainable route to diverse Zr-based MOFs.
| S-EPMC8981973 | biostudies-literature
Project description:Excessive accumulation of bilirubin in patients with hyperbilirubinemia can lead to tissue and organ damage and neurological diseases, and is even life-threatening in severe cases. Hemoperfusion is an effective method for removing bilirubin, but clinically used hemoperfusion adsorbents have unsatisfactory adsorption capacity and kinetics. In order to obtain a safe and efficient bilirubin adsorbent, Zr-based Metal-Organic Framework (MOF) material UiO-66 with high specific surface area and aqueous medium stability was prepared and modified with varying degrees of amination to improve its adsorption capacity. According to adsorption experiments in aqueous solution and simulated plasma, it was confirmed that the unsaturated coordinated zirconium in UiO-66 can effectively induce the aggregation and precipitation of free bilirubin unbound to albumin and the amino group on UiO-66-NH2 has a strong affinity for albumin bound bilirubin. The adsorption effect of UiO-66-NH2 with a high degree of amino modification is significantly stronger than that of UiO-66-NH2 with a low degree of modification. In simulated plasma with a bilirubin concentration of 40 mg dL-1, the adsorption capacities of UiO-66 and UiO-66-NH2-1.9 can reach 69.08 mg g-1 and 81.13 mg g-1. The adsorption isotherm fitting and adsorption kinetics fitting results also show that UiO-66 and UiO-66-NH2 are good adsorbents for bilirubin. In dynamic adsorption, the adsorbents also showed good performance and did not affect the protein in the plasma. The hemolysis test, coagulation time test, and cytotoxicity test confirmed that the bilirubin adsorbents based on UiO-66 and UiO-66-NH2 have good blood compatibility and biocompatibility. This study provides new ideas for the development of a novel bilirubin adsorbent and a theoretical basis for the study of bilirubin adsorption mechanisms.
| S-EPMC10691446 | biostudies-literature