Mesoporous Alumina-Supported Amines as Potential Steam-Stable Adsorbents for Capturing CO2 from Simulated Flue Gas and Ambient Air

Carbon management by a means of CO 2 capture from large stationary sources such as coal-fired power plants or from ambient air is a significant global issue. In the context of steam-stripping as a regeneration process for solid CO 2 adsorbents, new adsorbent materials robust enough for direct contact with low temperature steam are needed. Here, mesoporous γ-alumina-supported poly(ethyleneimine) composite materials are prepared and evaluated as effective CO 2 adsorbents, using dilute CO 2 streams such as simulated flue gas (10% CO 2 ) and ultradilute streams such as simulated ambient air (400 ppm CO 2 ). In comparison to the silica-supported amine adsorbents typically utilized for CO 2 capture applications, the alumina-supported amine adsorbents give better performance in terms of both capture capacity and amine efficiency, in particular, at ambient air conditions. In addition, the alumina-supported amines are stable over short multicycle temperature swing tests and, more importantly, appear to be more robust than the silica-based counterparts upon direct contact with steam. Thus, the resulting alumina-supported amines are suggested to be promising new materials for CO 2 capture processes equipped with steam-stripping regeneration, especially from ultradilute gas streams.