Promoted carbon dioxide capture via Immobilizing polyethyleneimine and ionic liquid to mesoporous SAPO-34

The main challenges encountered for supported amine sorbents in carbon dioxide (CO₂) capture are the low CO₂ diffusion and high desorption heat. In this work, we immobilized a mixture of low-viscosity ionic liquid (IL) 1-butyl-3-methylimidazole acetate with high affinity for CO₂ and polyethyleneimine (PEI) onto the prepared mesoporous molecular sieve SAPO-34. The apparent sorption/desorption rates were enhanced distinctly, and the time to reach equilibrium was shortened down to 30 min. For comparison, the corresponding time for SAPO-34-PEI was up to 150 min. A low desorption heat of approximately 1.281 to 1.423 GJ t⁻¹ CO₂ was achieved, which is lower than that of the PEI-loaded materials with a value > 1.5 GJ t⁻¹ CO₂. Meanwhile, the hybrid sorbent (SAPO-34-PEI-IL) enhanced CO₂ sorption capacities compared to SAPO-34-PEI and SAPO-34-IL, i.e., 135 % and 137 % increases, respectively, and exhibited excellent sorption–desorption cycle stability, retaining over 95 % of the initial sorption capacity after 24 cycles. This work presents a novel approach for the supported amine sorbent to be utilized for CO₂ capture in the future.