Synthesis and CO2 adsorption kinetics of Aluminum Fumarate MOFs pellet with high recovery

Abstract

As a promising CO2 adsorbent, Aluminum Fumarate (AlFu) metal organic frameworks (MOFs) were explored for pelletizing technology and CO2 adsorption characteristics. The effects of binder type (sodium carboxymethylcellulose (CMC), aluminum sol (AS)) and content (2.5 wt%-20 wt%), CO2 partial pressure (0.3 bar–1 bar) and temperature (35 °C–65 °C) on the mechanical performance and adsorption process were investigated. The results revealed that with the increase of binder mass, the pellet mechanical strength rose while the CO2 adsorption amount decreased. The AlFu pellet with 2.5 wt% CMC could retain the powder porosity and adsorption capacity. The mechanical strength of AlFu@CMC-2.5 wt% achieved 1.486 MPa, and the maximum adsorption capacity was 1.26 mmol/g at 35 °C and 1.0 bar. The CO2 adsorption capacity was increased with lower adsorption temperature and higher CO2 partial pressure. Compared with pseudo second order model and pseudo first order kinetic model, Avrami kinetic model could better describe the CO2 adsorption behavior of AlFu pellet. It indicated that the adsorption process was not a single physical or chemical adsorption. The rate-limiting kinetic analysis showed that the CO2 adsorption rate was determined by film diffusion and intraparticle diffusion rather than inter-particle diffusion.