Hybrid Ionic Liquid–Silica Xerogels Applied in CO2 Capture

Applied Sciences

Sandra Einloft¹  Michele O. Vieira¹  AnaSofia D. Ferreira²  EuricoJ. Cabrita²  Aline S. Aquino³  Michèle O. de Souza³ 

[1] Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga, 6681. 90619-900 Porto Alegre/RS, Brazil;UCIBIO, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT-UNL), Campus da Caparica. 2829-516 Caparica, Portugal;Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves, 9500. 91501-970 Porto Alegre/RS, Brazil;

关键词: carbon dioxide;    imidazolium ionic liquids;    immobilization;    xerogel;    silica;   

DOI  :  10.3390/app9132614

来源: DOAJ

【 摘 要 】

The imidazolium-based ionic liquids (ILs) are solvents known for selectively solubilizing CO₂ from a gas CH₄/CO₂ mixture, hence we have produced new hybrid adsorbents by immobilizing two ILs on xerogel silica to obtain a solid−gas system that benefits the ILs’ properties and can be industrially applied in CO₂ capture. In this work, the ILs (MeO)₃Sipmim.Cl and (MeO)₃Sipmim.Tf₂N were used at different loadings via the sol−gel process employing a based 1-methyl-3-(3-trimethoxysylilpropyl) imidazolium IL associated to the anion Cl⁻ or Tf₂N⁻ as a reactant in the synthesis of silica xerogel. The CO₂ adsorption measurements were conducted through pressure and temperature gravimetric analysis (PTGA) using a microbalance. SEM microscopies images have shown that there is an IL limit concentration that can be immobilized (ca. 20%) and that the xerogel particles have a spherical shape with an average size of 20 µm. The adsorbent with 20% IL (MeO)₃Sipmim.Cl, SILCLX20, shows greater capacity to absorb CO₂, reaching a value of 0.35 g CO₂ / g adsorbent at 0.1 MPa (298 K). Surprisingly, the result for xerogel with IL (MeO)₃Sipmim.Tf₂N shows poor performance, with only 0.05 g CO₂ / g absorbed, even having a hydrophobic character which would benefit their interaction with CO₂. However, this hydrophobicity could interfere negatively in the xerogel synthesis process. The immobilization of ionic liquids in silica xerogel is an advantageous technique that reduces costs in the use of ILs as they can be used in smaller quantities and can be recycled after CO₂ desorption.

【 授权许可】

Unknown