Sharif Digital Repository

In the present work, adsorption of hydrogen molecules over a metal organic framework (MOF-5) has been investigated by using first principles density functional theory (DFT). Different strategies have been applied for improving hydrogen storage, i.e. metal doping, boron substitution and functionalization. The metal atoms used for enhancing hydrogen adsorption include Li, Ca and Sc. It is found that the binding energy between these metal atoms and MOF is not enough to prevent clustering. Therefore a number of carbon atoms are substituted by boron atoms and it is indicated that boron substitution enhances the binding energies, significantly. Also the results reveal that boron substituted MOF... 

In this study, first, the UiO-66-NH2 metal-organic frameworks (MOFs) were modified with graphene quantum dots (GQDs) to facilitate the water attraction on MOF surface as well as improve their compatibility/affinity with the polyamide layer matrix of forward osmosis (FO) membranes. Next, to fabricate a new type of thin-film nanocomposite (TFN) membranes, the synthesized GQDs@UiO-66-NH2 composites are incorporated into the polyamide (PA) selective layer of FO membranes during the interfacial polymerization reaction of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). The influence of the prepared fillers on the chemical structure, morphology, surface roughness and hydrophilicity of the PA... 

The adsorptive removal of terephthalic acid (TPA) and p-toluic acid (p-tol) by metal organic frameworks (MOF) of Cu-BTC, Fe-BTC, MIL-101(Cr) and MIL-53(Al) was investigated in this study. The influence of various factors including solution pH, contact time, and initial concentration of TPA and p-tol solutions on the adsorption behavior was evaluated. Different adsorption isotherms and kinetic models were used to fit experimental adsorption data. It was found that the Langmuir and Redlich-Peterson adsorption isotherms were adequate to represent the experimental data (R2 > 0.97) and that the adsorption kinetics was well-represented by a pseudo-second-order kinetic model (R2 > 0.98). The zeta... 

In this work, the adsorption of benzoic acid (BA) over metal organic framework of chromium-benzenedicarboxylates (MIL-101) is reported for the first time. The influences of pH, contact time, initial concentration, and temperature of BA solution on the adsorption behavior were investigated. The Langmuir adsorption isotherm was adequate to represent the experimental data (R2 > 0.99) and the adsorption kinetics was well-represented by a pseudo-second order kinetic model (R2 > 0.96). The zeta potential of MIL-101 decreased with increasing pH confirming the importance of electrostatic interactions between MIL-101 and BA as well as the importance of the large pore volume (1.32 m3/g) and large... 

In this study, Fe3O4@Au/metal-organic frameworks (Fe3O4@Au/MOF) nanocomposite with flower-like core-shell structure was successfully synthesized via a hydrothermal route. The as-prepared catalyst was characterized using different techniques such as FT-IR, XRD, TEM, EDX, VSM, TGA, BET, and ICP. This nanocomposite exhibited an excellent catalytic performance in selective oxidation of cyclohexene to 2-cyclohexene-1-one by using molecular oxygen as green oxidant. The influence of reaction conditions including, pressure of molecular oxygen, temperature, time, solvent, and amount of catalyst on conversion and selectivity of products were evaluated. The activation energy (Ea) of the reaction was... 

In present work, first, the water-stable metal–organic framework (MOF) nanocrystals, UiO-66-(F)4, were synthesized under green reaction condition and then some PES/PA thin-film nanocomposite (TFN) membranes were prepared using this synthesized nanocrystals (as modifier) and polyethersulfone (as the substrate). The obtained MOF and membranes were characterized by various characterization techniques such as FE-SEM, AFM, PXRD, contact angle measurements and FT-IR spectroscopy. Finally, the forward osmosis performance of the resultant membranes was evaluated by using different concentrations of NaCl as a draw solution and deionized water as a feed solution. Among all used membranes, the membrane... 

High-performance wearable electronic devices with the capability of converting mechanical force into electrical energy have been gaining increasing attention for biomedical monitoring applications. We present a novel wearable piezoelectric sensor based on a poly(vinylidene fluoride) (PVDF) nanofibrous membrane containing microporous zirconium-based metal-organic frameworks (MOFs) for arterial pulse monitoring. It is shown that the incorporation of 5 wt % of MOF greatly enhances the piezoelectric constant of the polymer fibrous mat by 3.4-fold without significant loss in its flexibility. The nanofibrous composite exhibits a peak-to-peak voltage of 600 mV under an applied force of 5 N, which... 

Sulfur dioxide (SO2) is one of the acidic components found in the flue gas that can harm industrial facilities and the environment. SO2 adsorption by metal-organic frameworks (MOFs) is an emerging method to effectively remove SO2 in low concentrations from the gas mixtures. In this study, amino-functionalized MIL-53(Al), i.e., NH2-MIL-53(Al), was synthesized through the solvothermal method and examined for SO2 adsorption at relatively moderate pressure and temperature (up to 2 bar, 25-80 °). According to the results of XRD, FT-IR, TGA, and DSC analysis, NH2-MIL-53(Al) demonstrated appropriate water, acid, and thermal stability. The SO2 adsorption capacity of NH2-MIL-53(Al) was 5.21 mmol.g-1... 

Higher than a standard level, the humidity provides a suitable environment for the pathogenic microorganisms to grow and increases energy consumption for cooling, increasing greenhouse gas emissions. Desiccant air-conditioning (DAC) is an effective method to reduce humidity and energy simultaneously. Conventional desiccants are not suitable for use as a desiccant in building air conditioners, mainly because of high regeneration temperature and other issues such as limited equilibrium capacity and hydrothermal and cyclic instability. Metal-organic frameworks (MOFs) are a novel class of porous crystalline materials without the disadvantages of traditional desiccants. They benefit from a huge... 

Herein, Kiwi peel activated carbon (AC), Materials Institute Lavoisier (MIL-88B (Fe), and AC/MIL-88B (Fe) composite were synthesized and used as catalysts to degrade Reactive Red 198. The material properties were analyzed by the FTIR, BET-BJH, XRD, FESEM, EDX, TGA, and UV–Vis/DRS. The BET surface area of AC, MIL-88B (Fe) and AC/MIL-88B (Fe) was 1113.3, 150.7, and 199.4 m2/g, respectively. The band gap values (Eg) estimated by Tauc plot method, were obtained 5.06, 4.19 and 3.79 eV for AC, MIL-88B (Fe) and AC/MIL-88B (Fe), respectively. The results indicated that the AC/MIL-88B (Fe) composite had higher photocatalytic activity (99%) than that of pure AC (79%) and MIL-88B (Fe) catalysts (87%)....