Improvement of adsorbent materials for CO2 capture by amine functionalized mesoporous silica with worm-hole framework structure

Abstract

Amine functionalized mesoporous silica MSU-J with 3-D connective channel is employed as an effective absorbent for CO2. CO2 adsorption measurements were conducted by gravimetry to investigate the effects of (i) framework structure, (ii) mesoporous structure, (iii) the type of organic amine, (iV) hydrolyzation treatment, (V) cycle performance. Comparing with tetraethylenepentamine (TEPA) functionalized SBA-15, TEPA functionalized MSU-J has lower gas diffusion resistance. The CO2 uptake of 25MSU-J is 139.6mg·g−1, which is almost 2.5 times than that of SBA-15 of 58mg·g−1 at 20wt% TEPA loading. The different textured MSU-J is synthesized at 25°C, 45°C, 65°C and impregnated with TEPA. 65MSU-J synthesized at 65°C exhibits the larger pore size (16.2nm) and CO2 adsorption capacity due to pore size instead of larger specific surface area is more feasible for CO2 diffusion. The MSU-J is impregnated with tetraethylenepentamine (TEPA), diethylenetriamine (DETA), triethylenetetramine (TETA). TEPA impregnated MSU-J possesses higher thermostability (200°C) and CO2 capture (164mg·g−1) than counterparts, due to higher N content and the stronger combination between support and amine. The regeneration of SiOH from SiOSi effectively improves the CO2 adsorption capacity. Both MSU-J and hydrolyzing MSU-J exhibit good cycle performance of CO2 capture after 6 times cycle.