Modelling CO2 adsorption dynamics onto amine-functionalised sorbents: A fractal-like kinetic perspective. (31st December 2018)

• Record Type: Journal Article
• Authors: Montagnaro, Fabio; Balsamo, Marco
• Is Part Of: Chemical engineering science. Volume 192(2018)
• Page Start: 603
• Page End: 612
• Publication Date: 2018-12-31
• Subjects: CO2 adsorption -- Amine-functionalised sorbents -- Fractal-like kinetics -- Intraparticle diffusion -- Porosimetric properties -- Statistical analysis; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2018.08.009
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Literature kinetic data of CO2 adsorption onto amine-based sorbents were modelled. The Vermeulen model in its canonical and fractal-like formulation was applied. The fractal-like model provided a superior fitting accuracy of dynamic data. Links fractal exponent/sorbent microstructure/adsorption capacity were determined. Abstract: In this article we applied a fractal-like Vermeulen model to describe kinetic data selected from literature case-studies for CO2 adsorption onto amine-functionalised sorbents. The statistical analysis based on the Akaike information criterion demonstrated a better fitting performance of the fractal-like model with respect to its canonical counterpart in describing experimental profiles of coverage degree in the entire time range explored. The canonical kinetic model generally provided a satisfying description of dynamic data only in the early stages of the process. The fractal model accounts for the presence of an instantaneous rate coefficient which ranged between orders 10 −2 and 1 min −1 . Parameters derived from the fractal-like model demonstrated that the diffusion process at the beginning of adsorption is enhanced when the sorbent has a pore network easily accessible for the adsorbate. This happens when the sorbent is characterised by a wider mean pore diameter and greater specific pore volume, and when the process temperature is raised. The heterogeneity parameter of the fractal-like model affects the time-decay of the adsorption rate coefficient. This parameter ranged between 0.16 and 0.85, and it is higher when the porous material is both rapidly occupied by CO2 molecules and displays a wider pore size distribution.