(417f) Carbon Dioxide Capture Using Amine-Functionalized Multi-Walled Carbon Nanotubes: Adsorption/Desorption Kinetics Studies and Effects of Flue Gas Contaminants

Industrial grade multi-walled carbon nanotubes (IG-MWCNTs) impregnated with tetraethylenepentamine (TEPA) are promising materials for solid sorbent-based CO₂ capture from large point sources. In this work, the adsorption/desorption kinetics of amine-impregnated IG-MWCNTs were examined at various temperatures, CO₂ partial pressure, and amine loadings. After evaluating four kinetic models for CO₂ adsorption, it was found that Avrami's fractional order kinetic model provided the best fitting for the adsorption behavior of CO₂. In order to find the optimal regeneration method, three desorption methods were evaluated for the regeneration of solid sorbents. Moreover, the tolerance of amine-impregnated IG-MWCNTs to trace flue gas contaminants was also investigated. It was found that H₂O, NO, and SO₂ had a minimal impact on CO₂ adsorption capacity at 323K, while CO₂ adsorption capacity decreased with increasing SO₂ concentration at high temperature. Further analysis showed that irreversible sulphate/bisulphite deposited onto the solid sorbent might contribute to the decrease of CO₂ adsorption capacity. Compared with silica-based adsorbents, the loss of CO₂ capacity of IG-MWCNTs-50 (9.530%) was much lower than that of MCM-41-50 (40.430%) under SO₂ concentration of 200 ppm in the presence of water vapor after 5 cycles.