Kinetic, Thermodynamic and Regeneration Studies for CO_2 Adsorption onto Activated Carbon

摘要

Removal of CO_2 from flue gases has become an effective way to mitigate the Green House Gas effects and Pressure swing adsorption (PSA) is a potential technique for removing CO_2 from a flue gas streams. Low cost and abundantly available, activated carbon (coconut fibre) is a suitable candidate sorbents in the PSA process for CO_2 adsorption. Adsorption tests have been carried out in a fixed-bed column, at different temperatures starting from 25℃ to 60℃ and at a pressure up to 1 bar in order to investigate both kinetic and thermodynamic parameters. Moreover, regeneration studies have been conducted in order to verify the possibility of activated carbon reutilization, to determine its CO_2 adsorption capacity within consecutive cycles of adsorption-desorption. It was established that the activated carbon has a good CO_2 adsorption capacity, likely related to its surface area and composition, as well as to the intrinsic nature of the solid. CO_2 adsorption rate increases with increase in pressure while increase in temperature reduces the adsorption capacity. Experimental results confirmed that CO_2 adsorption is a reversible process and that desorption temperature is the main controlling parameter. The experimental data was fitted with Langmuir model and fit well with the experimental data of 2.828 mol_(CO_2) kg_(cat)~(-1). The thermodynamics parameter shows that the CO_2 adsorption process is exothermic in nature.