Kinetics of CO2 adsorption on UTSA-16(Zn) metal–organic framework: thermal, compositional, and geometrical effects

Abstract

Capturing CO₂ from point sources is a necessary step to limit the negative impacts of climate change. Metal–Organic Frameworks (MOFs), known for their exceptionally high surface areas and porosities, have demonstrated huge promise for environmental pollution control. The next stage of their application requires the design of equipment and materials capable of performing CO₂ adsorption optimally and efficiently at scale. However, this requires an in-depth understanding of the kinetics associated with CO₂ adsorption on MOFs under different circumstances (different geometries (pellets), compositions and temperatures). We present the first detailed kinetic study of the adsorption of CO₂ on MOF UTSA-16(Zn), a strong potential candidate for industrial-scale CO₂ capture, in the presence of different polymer binders and at different temperatures. Non-linear regression data fitting confirmed that a mixed order model was most able to describe the adsorption data, suggesting a combined controlling nature of surface adsorption and diffusion. Adsorption rate constants had an Arrhenius temperature dependency, and the calculated temperature independent kinetic parameters (activation energy and pre-exponential factor) allow the calculation of adsorption rates at any required design temperature. A potential reactor design and case study are also presented. The results provide valuable input to inform future design of adsorbent systems for CO₂ capture, facilitating the transition of MOFs to industrial scale applications to address urgent environmental challenges.