Enhanced CO2 capture capacity of amine-functionalized MOF-177 metal organic framework

In this study, MOF-177 was modified for the first time by amine groups to improve its CO2 adsorption capacity at low pressure, using three different amines polyethyleneimine (PEI), tetraethylenepentamine (TEPA), and diethylenetriamine (DETA) and a wet impregnation method. The formed adsorbents were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The CO2 adsorption performance of the amine-modified MOF-177 samples was evaluated from the adsorption kinetics. The results revealed that TEPA-modified MOF-177 powders, even at 20% loading, showed a significant improvement (4.8 times) in CO2 adsorption capacity compared to the parent MOF-177 at 298 K, while the PEI and DETA-modified samples showed relatively small improvements. With increasing temperature, CO2 adsorption capacity was increased to 4.6 mmol/g at 328 K, which is higher than those of previously reported-amine modified adsorbents (1.6–3.8 mmol/g at 318–348 K). MOF-177 powders with 20% TEPA were successfully made into pellets, which showed a slight decrease in capacity. The regenerability of MOF-177-TEPA-20% pellet was evaluated by performing adsorption-desorption cycles at 298 and 373 K, which showed a consistent CO2 capture performance.