Evaluating the Performance of a Microporous Ti Bisphosphonate MOF for Postcombustion Carbon Capture by Vacuum...

A multiscale study was carried out to evaluate the microporous -Ti-bisphosphonate MIL-91-(Ti) sorbent for postcombustion CO₂ capture in industrially relevant conditions. The process performance of the MOF was first assessed by using molecular simulated adsorption isotherms, which predicted an energy consumption of 1.65 MJ/kg and a productivity value of 0.42 mol/m³. Subsequently, this Ti-MOF was characterized using several complementary experimental techniques, and the characterization data were supplied to a process simulator to assess energy consumption and productivity values for 95% purity and 90% recovery targets. The experimental adsorption isotherms resulted in a better process performance, with a minimum energy consumption of 1.03 MJ/kg and a maximum productivity of 0.61 mol/m³. Such a discrepancy is likely to be due to the use of a generic force field that does not accurately capture host-guest intermolecular interactions in a highly confined environment of ultramicroporous MOFs like MIL-91. However, the lower energy consumption and higher productivity of this MOF, which are both desirable outcomes for CO₂ capture processes, suggest the viability of MIL-91-(Ti) for implications in real CCS applications.