Impregnation of SBA-15 with Task Specific Ionic Liquids for Targeted Gas Capture

Six task-specific ionic liquids (TSILs), comprised of the taurinate anion paired with five tetraalkylammonium cations (where alkyl = methyl, ethyl, propyl, butyl, and hexyl) and a tetrabutylphosphonium cation, were impregnated in SBA-15 to capture CO2. Additionally, a set of sorbents built from SBA-15 and a task specific ionic liquid that contains a sulfonic acid group were synthesized and investigated as a novel means of capturing ammonia from air. The results show that the sorption process is complex with the capacity of some samples being sensitive to preadsorbed water and some ionic liquids exhibiting crystallinity in the pores of SBA-15. The composite materials designed to capture ammonia show an increase in ammonia capacity below 2 kPa, while maintaining nearly the same capacity for ammonia as the parent silica at 101 kPa. More broadly, the results illustrate that it is possible to functionalize the pores of an adsorbent with an ionic liquid and that the functional group of the ionic liquid can be used to capture specific gases in a fixed-bed.