Abstract:

2-Aminoterephthalic acid and 4,4'-bipyridine ligand with Cu²⁺ ion was used to prepared three-dimensional(3D) anionic metal-organic framework, namely Cu(BDC-NH₂)(4,4'-Bipy)_0.5(BDC=terephthalicacid, Bipy=bipyridine)by hydrothermal method. By X-ray powder diffraction pattern(XRD), Fourier transform infrared spectrum(FT-IR), scanning electron micrographs(SEM), thermogravimetry(TG), N₂ absorption-desorption experiment, the composition, structure, morphology, stability and toleration of Cu(BDC-NH₂)(4,4'-Bipy)_0.5 were characterized. The adsorption property of the composites on methyl violet(MV) from aqueous solution was investigated. The effects of experimental parameters including the temperature, initial pH value and initial concentration of MV solution were discussed. The experiment data could be well described by the Langmuir equations with pseudo-second-order kinetic model. Thermodynamic parameters ΔG<0, ΔH<0 and ΔS<0 indicate that the MV adsorption onto Cu(BDC-NH₂)(4,4'-Bipy)_0.5 is spontaneous and endothermic, and the maximum adsorption capacity value reaches 60.09 mg/g at 193 K and pH=9, indicating that the adsorption ability of Cu(BDC)(4,4'-Bipy)_0.5 towards dyes can be improved by using amino modification..

Key words: three-dimensional metal organic frameworks, methyl violetadsorption