Carbon dioxide adsorption by zinc-functionalized ionic liquid impregnated into bio-templated mesoporous silica beads

Abstract

Novel high capacity hybrid sorbents for CO<inf>2</inf> capture have been developed based on zinc-functionalized ionic liquid (IL) impregnated into mesoporous silica beads derived from calcium alginate template beads. Pore modification and development of a surface-confined layer of IL synergistically enhanced the uptake capacity (up to 8.7wt%) and kinetics of these materials. Spectroscopic and thermophysical signatures of the IL impregnated materials confirm the existence of a highly confined IL layer at low IL:SiO<inf>2</inf> ratio, and multilayer-mimicking bulk phase at higher IL loading. Our results clearly demonstrate that developing a thin layer of zinc-functionalized IL onto porous silica beads effectively enhances the uptake kinetics by exposing interaction sites across a large surface area, and facilitating diffusion through the pore network of the support.