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The adsorptive removal of antibiotics, emerging organic pollutants in water is very important but challenging. In this work we report a series of eight water stable metal-organic framework (MOFs), which are methodically screened for the removal of metronidazole (MNZ) from water. It was found that two isostructural Zr(IV)-MOFs (UiO-66 and UiO-66-NH2) showed adsorption capacities of around 200.2 mg g(-1) and 265.5 mg g(-1), respectively, which are higher than the experimental values of reported porous materials used for MNZ removal so far. The MOFs were characterized by Powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy, Thermogravimetric analysis (TGA), Scanning electron microscope (SEM), Energy-dispersive X-ray elemental analysis (EDX), BET isotherm, UV-vis (UV-vis) spectrophotometer and NICOMPT 380 ZLS. The effects of various parameters including time, concentration, temperature and pH were investigated. The adsorption mechanism of UiO-66-NH2 for MNZ has also been explored through computational simulations. The results showed that MNZ molecules are mainly locate at around the -NH2 functional groups in pore surfaces of UiO-66-NH2, with the increase of molecular level of the amino groups, the affinity of the framework to MNZ could be significantly increased. The results demonstrated that highest adsorption uptake by UiO-66-NH2 was attributed to -NH2 functional group including with (hydrogen bonding interactions, electrostatic interaction and larger pHpzc). The adsorption process of the two MOFs fitted the pseudo-second-order kinetic model and Langmuir isothermal model, whilst the adsorption was endothermic, with the confirmation by thermodynamic studies.
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