Bifunctionalized Metal Organic Frameworks, UiO-66-NO2-N (N = -NH2, -(OH)2, -(COOH)2), for Enhanced Adsorption and Selectivity of CO2 and N2

Metal organic frameworks (MOFs), UiO-66-NO 2 and UiO-66-NO 2 –N (N = -NH 2, -(OH) 2, -COOH) 2 ), were synthesized under solvothemal conditions using different functionalized organic linkers. The synthesized samples were further activated by solvent exchange using methanol and chloroform. All samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and N 2 adsorption/desorption. Gas adsorption of CO 2 and N 2 on all samples has been evaluated at 760 mmHg and different temperatures. It was found that UiO-66-NO 2 -NH 2 by methanol or chloroform activation presented much higher CO 2 adsorption than other samples and the adsorption capacities are around (87 and 74) cm 3 ·g –1 on chloroform-activated and methanol-activated samples, respectively, at 273 K and 760 mmHg. In addition, high selectivity of CO 2 /N 2 has been found on chloroform-activated UiO-66-NO 2 -NH 2 giving a factor of 65 while the selectivity of CO 2 /N 2 is only 40 for chloroform-activated UiO-66-NO 2 .