# Functionalization of Ordered Mesoporous Silica (MCM-48) with Task-Specific Ionic Liquid for Enhanced Carbon Capture

## TL;DR

This study creates new materials by combining ionic liquids with silica to improve carbon capture efficiency and selectivity.

## Contribution

The functionalization of MCM-48 with amino acid-based ionic liquids enhances CO2 capture and selectivity over nitrogen.

## Key findings

- The composites preserved the thermal and structural integrity of MCM-48 after functionalization.
- The 40 wt.%-[Emim][Gly] composite showed a 10× and 5× increase in CO2 uptake compared to pure MCM-48.
- Composites with 40 wt.% [Emim][Ala] achieved a CO2/N2 selectivity of 17, significantly higher than 2 for pristine MCM-48.

## Abstract

This work presents new composites of AAILs@MCM-48 obtained by functionalizing ordered mesoporous silica MCM-48 with two amino acid-based ionic liquids (AAILs) ([Emim][Gly] and [Emim][Ala]) to improve carbon capture and the selectivity of CO2 over nitrogen. Thermogravimetric and XRD analyses of the composites showed that the MCM-48 support’s thermal and structural integrity was preserved after the AAILs were encapsulated. An N2 adsorption–desorption study at 77 K confirmed AAIL encapsulation in the porous support. Under post-combustion flue gas conditions, both [Emim][Gly]@MCM-48 and [Emim][Ala]@MCM-48 demonstrated improved CO2 adsorption in comparison to the unmodified MCM-48, with a CO2 partial pressure of around 0.15 bar. Regarding the maximal CO2 uptake, the 40 wt.%-[Emim][Gly] composite outperformed the others at 303 K, with values of 0.74 and 0.82 mmol g−1, respectively, at 0.1 and 0.2 bar. These numbers show a 10× and 5× increase, respectively, compared to the pure MCM-48 under identical conditions. In addition, the selectivity of the composites was improved significantly at 0.1 bar: the selectivity of composites containing 40 wt.% [Emim][Ala] increased to 17, compared to 2 for pristine MCM-48. These composites outperform other silica-based studies reported in the literature, even those using amines as solvents. The presented composites offer therefore promising prospects for advancing carbon capture technology.