Enhanced CO₂ Capture through SAPO-34 Impregnated with Ionic Liquid

The concurrent utilization of an adsorbent and absorbent for carbon dioxide (CO₂) adsorption with synergistic effects presents a promising technique for CO₂ capture. Here, 1-butyl-3-methylimidazole acetate ([Bmim][Ac]), with a high affinity for CO₂, and the molecular sieve SAPO-34 were selected. The impregnation method was used to composite the hybrid samples of [Bmim][Ac]/SAPO-34, and the pore structure and surface property of prepared samples were characterized. The quantity and kinetics of the sorbed CO₂ for loaded samples were measured using thermogravimetric analysis. The study revealed that SAPO-34 could retain its pristine structure after [Bmim][Ac] loading. The CO₂ uptake of the loaded sample was 1.879 mmol g^-1 at 303 K and 1 bar, exhibiting a 20.6% rise compared to that of the pristine SAPO-34 recording 1.558 mmol g^-1. The CO₂ uptake kinetics of the loaded samples were also accelerated, and the apparent mass transfer resistance for CO₂ sorption was significantly reduced by 11.2% compared with that of the pure [Bmim][Ac]. The differential scanning calorimetry method revealed that the loaded sample had a lower CO₂ desorption heat than that of the pure [Bmim][Ac], and the CO₂ desorption heat of the loaded samples was between 30.6 and 40.8 kJ mol^-1. The samples exhibited good cyclic stability. This material displays great potential for CO₂ capture applications, facilitating the reduction of greenhouse gas emissions.