A robust aluminum-octacarboxylate framework with scu topology for selective capture of sulfur dioxide.

The high structural diversity and porosity of metal-organic frameworks (MOFs) promote their applications in selective gas adsorption. The development of robust MOFs that are stable against corrosive SO2 remains a daunting challenge. Here, we report a highly robust aluminum-based MOF (HIAM-330) built on a 4-connected Al3(OH)2(COO)4 cluster and 8-connected octacarboxylate ligand with a (4,8)-connected scu topology. It exhibits a fully reversible SO2 uptake of 12.1 mmol g-1 at 298 K and 1 bar. It is capable of selective capture of SO2 over other gases (CO2, CH4, and N2) with high adsorption selectivities of 60, 330, and 3537 for equimolar mixtures of SO2/CO2, SO2/CH4, and SO2/N2, respectively, at 298 K and 1 bar. Breakthrough measurements verified the capability of HIAM-330 for selective capture of SO2 (2500 ppm) over CO2 or N2. High-resolution synchrotron X-ray powder diffraction of SO2 loaded HIAM-330 revealed the binding domains of adsorbed SO2 molecules and host-guest interactions.