Search

AbstractIn this report we present a simple synthesis of a nickel-based metal organic framework (MOF-Ni) at the room temperature using a solution of dimethylformamide (DMF), ethanol and distilled water. The MOF-Ni synthesized in various solvents displayed numerous different properties and advantages over other materials including easy synthesis procedure, good crystallinity, rigidity, and robust chemical stability. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) were employed to analyze the as-synthesized MOF-Ni. The as-obtained MOF-Ni was used to investigate its adsorption kinetics of red telon dye (RTL) molecules. The effects of time (30–270 min), initial RTL concentration (20–300 mg/L), adsorbent dose (2–50 mg), solution pH (2–12), and temperature (10–80 °C) were investigated. The pseudo-first order rate equation was able to provide the best description of the adsorption kinetics data in the studied time scale. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms, and the isotherm constants were also determined. Dye adsorption turned out to strongly depend on pH, and a low pH was found to increase the amount of adsorbed dyestuff. Compared with other samples, MOF-Ni synthesized in (DMF ​+ ​C2H5OH ​+ ​H2O) had a significantly enhanced adsorption ability for RTL dye. The MOF-Ni high adsorption capacity for RTL dye was attributed to the electrostatic attraction/repulsion phenomena. Moreover, MOF-Ni showed an improved stability at 370, 417, and 423 °C temperatures. The results obtained through our experiments suggested that our porous MOF-Ni microstructures synthesized in DMF ​+ ​C2H5OH ​+ ​H2O have potential applications for treating wastewaters containing RTL dyes. [ABSTRACT FROM AUTHOR]

Green application of a high-nitrogen, zeolite-like, porous metal–organic framework, IFMC-1 (Institute of Functional Material Chemistry), is reported for dye pollutant removal and wastewater treatment. The IFMC-1 contained a high-nitrogen-content ligand without an NH2 group (H3dttz), dimethylacetamide, and Zn ion. The synthesis of H3dttz from diaminomaleonitrile was initiated after closure of the triazole ring and formation of 4,5-dicyano-2H-1,2,3-triazole as an intermediate material; thus, two tetrazole rings were obtained in a 1,3-dipolar cycloadditionn. Only four nitrogens of the IFMC-1 ligand coordinate with zinc, and 63.6% of the nitrogens are free. The IFMC-1-based tetrazole without an NH2 group was investigated for removal of methylene blue (MB) and basic red 46 (BR-46) pollutants. The results indicated that the IFMC-1 adsorbent effectively removed the MB and BR-46 dyes from solution. The contaminant adsorption capacity of IFMC-1 for MB and BR-46 was 293.9 and 135.2 mg g–1, respectively. Investigation of isotherm and kinetic data of dye removal using the synthesized absorbent indicated that it follows the Langmuir isotherm and pseudo-second-order kinetics. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and characterization of Zn2+ decorated (adipic and terephthalic acid as linkers) piperazine-based metal-organic framework (P-MOFs) and their extraction behavior toward the Chicago sky blue (CSB) dye. The formation of Zn2+-decorated P-MOFs was confirmed by FT-IR spectroscopy, energy-dispersive spectroscopy, X-ray diffraction, BET surface area analysis and TGA. Adsorption behavior of the synthesized P-MOFs was explored through solid-phase adsorption (batch method) prior to UV-Vis spectrophotometric determination. Adsorption parameters, including adsorbent dosage, pH of solution, dye concentration, and time, were optimized. Excellent percentage removal of 94% and 95% for AP-Zn-MOF and TP-Zn-MOF, respectively, was achieved at pH 7.5. Kinetics studies indicated that the synthesized adsorbents AP-Zn-MOF and TP-Zn-MOF followed the pseudo-second-order rate model with R2 value 0.9989. The Freundlich isotherm with high R2 value as compared to Langmuir isotherm indicated that CSB adsorption for the synthesized MOFs follows multilayer adsorption. [ABSTRACT FROM AUTHOR]

Cadmium as a highly toxic metal is released into the environment through paper production, metal processing, phosphate fertilizers, insecticides, and treatment of wastewater. Cadmium also inhibits the body activities and is very toxic for kidney and other organisms. In the current study, zinc-based metal–organic framework, zeolitic imidazolate framework (ZIF)-8, was synthesized and modified by dimethylethylenediamine (ZIF-8-mmen) for the removal of cadmium. To optimize the experiments, response surface methodology was applied with three variables including pH, adsorbent dosage, and contact time using central composite design. The optimum conditions for pH, dosage, and time were 2, 0.1 g, and 89 min, respectively, with removal efficiency of 85.38%. The Langmuir isotherm (qm = 1000 mg/g) indicates the monolayer adsorption. The kinetic studies reveal that the Lagergren model was predominant and cadmium was not chemisorbed. Thermodynamic parameters show spontaneous, endothermic, and physisorption processes. [ABSTRACT FROM AUTHOR]