F-MOF-based Mixed Matrix Membranes for an energetically favourable separation of CO2

Excessive emission of greenhouse gases is responsible for the global climate change. Unfortunately capture and separation of such gases are difficult and expensive.[1] Since 1970, polymeric membranes have been used for separation of gas mixtures offering satisfactory results at low energy costs. The key parameters for a good-quality membrane are the permeability and selectivity which are trade-off parameters, and thus related to an upper bound that must be achieved to have satisfying results.[2] Recently, Mixed Matrix Membranes (MMMs) have emerged as a new generation of promising materials for gas separation. MMMs combine the strength points of polymers with the highest adsorption capacity of porous fillers. This work presents an Italian project named doMino concerning the synthesis and advanced characterization of a new generation of MOF-based MMMs for CO2 separation. Novel MOFs containing per-fluorinated linkers are synthesized and deeply characterized. Structural and adsorptive properties are evaluated via spectroscopic techniques (IR and Raman but also SSNMR) coupled with volumetric and microcalorimetric analysis. MMMs are prepared by mixing Hyflon AD60x and novel F-MOF, specifically F4_MIL140(Ce) and F4_UiO66(Ce), at different concentrations as self-standing dense films and tested in terms of gas transport properties. Spectroscopy techniques are used to understand the properties of the final MMMs, and volumetric analysis at low pressure (up to 1 bar) allows evaluating which are the most promising MMMs that present better properties than their neat polymers, exploiting the great adsorption capacity of new F-MOFs. References [1] Sholl, D. S., & Lively, R. P. (2016). Seven chemical separations to change the world. Nature, 532(7600), 435-437. [2] Robeson, L. M. (2008). The upper bound revisited. Journal of Membrane Science, 320(1), 390-400.