Binary Adsorption of Carbon Dioxide and Water Vapor on Amine-Impregnated Silica
Yongqiang Wang, Chengguang Chen, Gang Kevin Li
Abstract
Amine-impregnated materials are considered crucial adsorbents for carbon capture from wet streams due to the enhancement of CO 2 adsorption in the presence of moisture. Nevertheless, there have been limited studies conducted to explore the coadsorption of water vapor and CO 2 on impregnated amines, resulting in challenges when modeling the binary adsorption behavior. In this study, single and binary component isotherms for the adsorption of CO 2 and H 2 O on polyethylenimine-impregnated silica were analyzed and modeled using a realistic interactive Langmuir-BET (RBET) adsorption theory. Compared with single-component adsorption results, CO 2 adsorption capacities on amines were found to be enhanced by moisture, whereas water loadings were reduced when CO 2 was present. The RBET model, incorporating the interactions between CO 2 and adsorbed water, demonstrated excellent accuracy in describing the observed adsorption behavior. The binary adsorption capacities under different conditions were further calculated to guide the practical application of amine-impregnated adsorbents for carbon capture.