ZIF-67 and MCM-41/ZIF-67 composites were successfully synthesized with water solvent at room temperature. The amounts of MCM-41 added during synthesis were varied at 2.5, 5 and 10 (%w/w) toward the amount of ZIF-67, and the obtained solids were denoted as MC (2.5)/ZIF-67, MC (5)/ZIF-67, and MC (10)/ ZIF-67, respectively. The X-ray diffraction (XRD) patterns of ZIF-67 and the composites showed characteristic peaks at 2θ of 7.32, 10.36, 12.69, 14.66, and 16.40°, similar to that of reported ZIF-67. The Fourier transform infra-red (FT-IR) spectra of all solids showed absorption bands at the same wavenumbers as reported for ZIF-67. The results of surface morphology analysis using scanning electron microscope (SEM) have shown that ZIF-67 and the composites have a cube shape, which is characteristic for the ZIF-67 standard. N 2 adsorption-desorption data showed that the specific surface area of ZIF-67 and MC (5)/ZIF-67 were 1079.2 and 1011.2 m 2 /g, respectively, lower than that of MC (10)/ZIF-67 (1250.6 m 2 /g). However, results of thermal gravimetric analysis (TGA) showed that the thermal stability of MC (10)/ZIF-67 reached 357°C, higher than that of ZIF-67 (325°C). Performance of the composites as adsorbent of methyl orange (MO) in aqueous solution showed that the MC (5)/ZIF-67 had the highest adsorption capacity of 167.635 mg/g, and followed the pseudosecond-order adsorption kinetics and Langmuir isothermal adsorption.
Metal-organic frameworks type HKUST-1 were synthesized using a solvothermal method with reactants of copper(II) nitrate trihydrate and benzene-1,3,5-tricarboxylic acid in a solvent mixture of ethanol, DMF and water with a volume ratio of 1:1:1. The synthesis of HKUST-1 was carried out by adding cetyltrimethylammonium bromide (CTAB) surfactant and acetic acid as a modulator. The process of synthesis was done in a vial bottle at a temperature of 100 °C for 10 h. The obtained solids, in the form of a light blue colored powder, were characterized by X-Ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and nitrogen adsorption-desorption methods. The diffraction patterns of the obtained solids show the characteristic peaks of the HKUST-1 at 2θ of 6.7, 9.5, 11.5 and 13.4°, respectively. The surface morphology of the synthesized HKUST-1 was octahedral forms with a particle size of between 16.4-17.9 µm. The HKUST-1 obtained with the addition of CTAB surfactant had a nitrogen adsorption-desorption isotherm of type IV, characteristic to a mesoporous material, with a specific surface area as high as 1010 m 2 /g and pore diameter of 9.2 nm.
AbstractMOF-5 (metal-organic frameworks-5) have been synthesized using solvotermal method in which reaction mixtures of zinc nitrate hexahydrate and benzenedicarboxylic acid in dimethylformamide were heated at various heating temperatures and times in order to obtain the best reaction conditions for the synthesis of MOF-5. The heating temperatures used were 105, 120 and 140 °C, respectively with heating times of 12-144 hours. Determination of the best reaction conditions was based on the observation of phase purity and crystal morphology of MOF-5 using XRD and SEM. The characterization results showed that optimization of MOF-5 crystals were obtained when the reaction mixtures were heated at 105 °C for 144 h, 120 °C for 24 h and 140 °C for 12 h. The maximum weight of MOF-5 crystal was generated from reaction mixture heated at 120 °C for 72 h.
Metal-organic frameworks (MOFs) are promising crystalline materials for various application due to their controllable porous structure and large specific surface area. Their properties can be further improved by several means, such as making a binary MOF comprising of two different MOFs. In this research, UiO-66/HKUST-1 composites have been synthesized by solvothermal method, in which the UiO-66 was prepared at 120 °C for 24 h in N, N-dimethylformamide (DMF) prior to preparation of HKUST-1 at 100 °C for 10 h in solvent mixture of DMF, ethanol and water. Amounts of Zr2+ for the synthesis of UiO-66 added during the synthesis process were varied at 5, 10 and 20% toward the amount of Cu2+ for synthesis of HKUST-1. Diffractogram patterns of the obtained composites showed dominant characteristic peaks, similar to that reported for HKUST-1. Furthermore, FTIR spectra of all solids showed absorption bands at the same wavenumbers as reported for HKUST-1. Transmission Electron Microscopy (TEM) images showed the spread of Zr metal evenly on the pore of composites.
UiO-66, as one of the metal-organic framework (MOF) compounds, has been used to treat some anionic and cationic dye waste. In order to determine the adsorption selectivity decisively, the synthesis of UiO-66 and UiO-66 modulated with acetic acid had been carried out, along with their adsorption tests for Eriochrome Black T (EBT) dye solution. The synthesis was performed by utilizing a solvothermal method with the reaction mixtures of zirconium (IV) chloride (ZrCl4) and terephthalic acid (H2BDC) as a ligand heated at 120 oC for 24 hours. Both UiO-66 (without acetic acid) and acetic acid modulated UiO-66 were obtained as a white powder. Acetic acid as a modulator was added and being investigated for the adsorption capability compared to the normal UiO-66. This study showed that normal UiO-66 exhibited better adsorption than acetic acid modulated UiO-66 with a mmol ratio of acetic acid:ligand varied from 50:1, 100:1, and 150:1. Acetic acid modulated UiO-66 with a mmol ratio of 50 exhibited the best crystallinity as observed by using x-ray diffraction. It can be concluded that the adsorption of EBT using normal and acetic acid modulated UiO-66 obeyed the pseudo-second-order reaction rate law as well as the Langmuir adsorption isotherm pattern.
Synthesis of ZIF-8 (zeolitic Imidazolate Frameworks-8) have been successfully carried out by the reaction of zinc nitrate and 2-methylimidazolate in DMF (N'N-dimethylformamide) solvent at a temperature of 120 °C for 24 hours. Synthesis of ZIF-8 has been conducted five times with variations molar ratio of metal (Zn2+):ligand (MeIM) consecutive 1:1; 1:1.5; 1:2; 1:2.5 and 1:3 to study the influence of metal-ligand ratio of the crystallinity and morphology of ZIF-8 that was produced. The results of characterization by X-ray diffraction, FTIR and SEM show that ZIF-8 is synthesized with a ratio of metal: ligand = 1:2 showed the highest crystallinity and has the most irregular surface morphology with form box.
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