Triazole ionic liquid composites with tailored ultra-micropores and dispersed active sites for highly-efficient capture of low-concentration CO2

Novel TIL@SBA-15 composites with ultra-micropores and active sites are fabricated. • Optimized composites achieve high CO 2 uptake and exceptional CO 2 /N 2 selectivity. • The composites maintain high CO 2 uptake under humid gas conditions. • Over 95% of initial CO 2 capacity is retained after 15 adsorption-desorption cycles. • Superior per0066ormance stems from synergy of chemical and physical adsorption. To address the critical challenge of capturing low-concentration CO 2 from real industrial flue gas, this study developed triazole ionic liquid (TIL)@SBA-15 composites featuring a novel ultra-microporous structure (<0.70 nm) by immobilizing choline triazolide ([Cho][Triz]) and 1-ethyl-3-methylimidazolium triazolide ([Emim][Triz]) into the mesoporous molecular sieve SBA-15. The obtained composites exhibited excellent CO 2 separation performance and cyclic stability under both dry and humid gas conditions. At 298 K, the 70 wt% [Cho][Triz]@SBA-15 and 70 wt% [Emim][Triz]@SBA-15 achieved CO 2 adsorption capacities of 54.4 and 65.4 mg CO 2 /g adsorbent in a humid gas (10% CO 2 and 1% H 2 O balanced with N 2 ), close to their dry-condition capacities (60.3 and 67.0 mg CO 2 /g adsorbent, 10% CO 2 balanced with N 2 ). Moreover, over 95% of the initial adsorption capacity was retained after 15 consecutive adsorption–desorption cycles whether under dry or humid gas conditions. This superior performance originated from the synergistic effect of chemical adsorption by N-electronegative sites and physical adsorption by the novel ultra-microporous structures from the spatially confined and uniformly dispersed TILs within the SBA-15. This work provides a promising design strategy for TIL-based adsorbents that combine high CO 2 capture efficiency with robust stability, thereby advancing efficient recovery of low-concentration CO 2 from industrial flue gas. Download: Download high-res image (207KB) Download: Download full-size image