A systematic evaluation of UiO-66 metal organic framework for CO2/N2 separation

Abstract

A systematic investigation of the metal organic framework UiO-66 for CO2/N2 separation was studied. Adsorbent powder was shaped into pellets using poly vinyl alcohol (PVA) as the binder. The ratio of MOF to binder was varied to obtain the desired characteristics for the pellets. The CO2 and N2 equilibrium adsorption isotherms were measured on powder and pellets using a standard volumetric adsorption apparatus. About 14% decrease in CO2 adsorption capacity was observed after pelletization. Although, a reduction in specific loadings was observed, the change in volumetric capacity was lower, due to the increase in bulk density after pelletization. The breakthrough experiments conducted in a column containing about 10 g of the UiO-66 (at 1.3 bar and 300 K) reveal preferential adsorption of CO2 over N2 and the CO2 separation. The process performance of UiO-66 was evaluated in three different PVSA cycles using the single column. The inclusion of purge and rinse step result in an increase of N2 product purity and CO2 product purity respectively. The findings from PVSA suggest that UiO-66 is a promising material for CO2/N2 separation at low CO2 concentrations, however a multi-bed PVSA may be needed to meet the process performance parameters for industrial requirement.