In Situ Synthesis And Application Of Task-Specific Ionic Liquids Within Porous Materials

Carbon dioxide is the single most important anthropogenic greenhouse gas in theatmosphere, contributing63.54%to the overall global radiative forcing. There is anestablished link between increasing CO₂emissions and global climate change. CO₂captureand storage （CCS） is a possible mitigation option for limiting emission of CO₂, and the cost ofmitigating climate change can be decreased compared to strategies where only other climatechange mitigation options are considered. Absorption with ionic liquids （ILs） is one of themost promising technologies for capturing CO₂. A series of task-specific ionic liquidscontaining amine functional groups have been demonstrated to have much better capacitiesfor CO₂capture due to their higher reactivity with CO₂.A number of studies have been performed to explore the prospect of immobilizing ILs,such as supported ionic-liquid membranes and polymerized ILs. In this work, a strategy, socalled ship-in-a-bottle synthesis, was adopted to immobilize ILs within zeolite supercages.The prepared samples were analyzed by FT-Raman spectroscopy, TGA, elemental analysis,breakthough adsorption experiment and CO₂-TPD.The non-amine-functionalized ionic liquids,1-alkyl-3-methyl-imidazolium bromide（[C_nMIm]Br， n=4，6，8and10）, and amine-functionalized ionic liquid,1-（3-aminopropyl）-3-methyl-imidazolium bromide （[APMIm]Br）, were synthesized withinthe supercages of NaY zeolite were reported. The host-guest systems have abnormalFT-Raman spectra when comparing with bulk ILs. This phenomenon should be attributed tounusual changes in the symmetry and coordination geometry of the molecules confined in ananoscale space.The interaction of CO₂with these host-guest systems were investigated by breakthroughadsorption method and temperature-programmed-desorption （TPD） method. The resultsreveal characteristic chemisorptions behavior of these novel sorbents on CO₂capture. Thisindicates that there is weak chemical interaction between CO₂and amine functional groups,and the adsorbed CO₂can be fully desorbed at low temperature. Hence, the energyconsumption of sorbent regeneration can be reduced.