CO2 capture using silica-immobilized dicationic ionic liquids with magnetic and non-magnetic properties

Evandro Duarte; Franciele Bernard; Leonardo Moreira Dos Santos; Barbara B Polesso; Rafael Duczinski; Vitor Forneck; Julian Geshev; Sandra Einloft

doi:10.1016/j.heliyon.2024.e29657

CO₂ capture using silica-immobilized dicationic ionic liquids with magnetic and non-magnetic properties

Heliyon. 2024 Apr 15;10(8):e29657. doi: 10.1016/j.heliyon.2024.e29657. eCollection 2024 Apr 30.

Authors

Evandro Duarte^{1

2}, Franciele Bernard², Leonardo Moreira Dos Santos², Barbara B Polesso^{1

2}, Rafael Duczinski^{1

2}, Vitor Forneck², Julian Geshev³, Sandra Einloft^{1

2}

Affiliations

¹ Post-Graduation Program in Materials Engineering and Technology, Pontifical Catholic University of Rio Grande do Sul - PUC, RS, Brazil.
² School of Technology, Pontifical Catholic University of Rio Grande do Sul - PUC, RS, Brazil.
³ Institute of Physics, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Abstract

The need to find alternative materials to replace aqueous amine solutions for the capture of CO₂ in post-combustion technologies is pressing. This study assesses the CO₂ sorption capacity and CO₂/N₂ selectivity of three dicationic ionic liquids with distinct anions immobilized in commercial mesoporous silica support (SBA- 15). The samples were characterized by UART-FTIR, NMR, Raman, FESEM, TEM, TGA, Magnetometry (VSM), BET and BJH. The highest CO₂ sorption capacity and CO₂/N₂ selectivity were obtained for sample SBA@DIL_2FeCl₄ [at 1 bar and 25 °C; 57.31 (±0.02) mg CO₂/g; 12.27 (±0.72) mg CO₂/g]. The results were compared to pristine SBA-15 and revealed a similar sorption capacity, indicating that the IL has no impact on the CO₂ sorption capacity of silica. On the other hand, selectivity was improved by approximately 3.8 times, demonstrating the affinity of the ionic liquid for the CO₂ molecule. The material underwent multiple sorption/desorption cycles and proved to be stable and a promising option for use in industrial CO₂ capture processes.

Keywords: CO2 capture; Dicationic ionic liquid; Magnetic dicationic ionic liquids; Mesoporous silica supports.