Development of polymer-based membranes for olefin/paraffin gas separations

Membrane technology offers an interesting alternative for existing purification technologies in C2 and C3 olefin/paraffin separations. Nowadays, such mixtures are separated by energy-intensive distillation, consuming an estimated 35 GWh in the US alone. Unfortunately, the separation of olefins and paraffins is extremely hard owing to their similar size and boiling points. Hence, the current generation of polymer membranes show rather limited separation performance in terms of olefin/paraffin selectivity and olefin permeance. Therefore, this dissertation introduces several new strategies based on facilitated transport to acquire high-performance membranes for C2 and C3 separation. In a first section, carboxylated polymers (i.e. 6FDA-DAM/DABA and PIM-1) will be functionalized with Ag(I) and Cu(I) ions in order to selectively target the double bond of the olefin. Next, MOFs can be introduced to the polymer matrix. MOFs are able to fixate the Ag and Cu ions, mitigating frequently occurring stability issues. In a final part of the PhD, the project will center around membranes based on ionic liquids. Besides directly synthesizing poly-ionic liquid membranes, two ionic liquids that are specifically designed to have high olefin affinity will be used as mobile carriers in isoporous supports.