CO2 capture on activated carbon from PET (polyethylene terephthalate) waste: Kinetics and modeling studies

CO2 emissions from flue gases can be restricted via a promising post-combustion capture technique, namely, adsorption. In the present work, behavior of adsorbents, prepared from PET (polyethylene terephthalate) waste, for CO2 capture studies was investigated to understand the fixed bed adsorption dynamics. The effect of activation on textural properties, surface functional groups and elemental composition was studied through nitrogen adsorption/desorption, XPS, FTIR, and EDX analysis. Thermal stability of adsorbent samples was also evaluated. The kinetics of the adsorption process was studied using Lagergren’s pseudo-first-order model, pseudo-second, fractional order, Elovich, and Avrami models. Freundlich isotherm fit confirmed the heterogeneous nature of adsorbent’s surface. Adsorption column breakthrough profiles were modeled using linear driving force (LDF) approximation for mass transfer. Model equations were solved using the Method of lines in MATLAB environment. Results show that the model closely approximated the column breakthrough curves for different CO2 concentrations (5–12.5%) and different adsorption temperatures (30–100 °C).