Improvement of SO2/CO2 separation performance in a Hofmann-type metal-organic framework with functional amino groups

Utilizing adsorbents for the capture of SO2 represents a cost-effective and energy-saving. Metal-organic frameworks (MOFs) , known for their high porosity and amenability to functionalization, are particularly adept at SO2 adsorption. We have incorporated an amino group into the NiNi-PYZ MOF. Due to the interaction between the amino group and SO2 molecules, causing the NiNi-PYZ-NH2 to orient towards the amino group within the pore channels. Concurrently, this interaction reduces the distance between the oxygen atoms and the open metal sites (OMS). The collaborative action of the open metal sites and functional groups on SO2 notably boosts selectivity and packing density. The modified NiNi-PYZ-NH2 exhibits a packing density of 0.64 g/mL and a SO2/CO2 selectivity of 54.80, outperforming the original NiNi-PYZ. NiNi-PYZ-NH2 facilitates adsorption of SO2, making it a recyclable adsorbent for SO2. This study offers a strategic approach to designing materials for SO2 separation with enhanced selectivity and packing density.