Adsorption of CO₂ by surface modified coal-based activated carbons: kinetic and thermodynamic analysis

Abstract

The effects of different surface modifiers on the CO2 adsorption capacity of coal-based activated carbons were studied, and the diffusion behavior, adsorption kinetics and thermodynamic parameters of CO2 in activated carbons were analyzed. The results show that compared with ethylene glycol, 1,2-propylenediamine and zinc chloride, potassium hydroxide and sodium hydroxide can greatly improve CO2 adsorption capacity. The adsorption rate is faster, and the adsorption capacity is larger, with the maximum CO2 adsorption capacity being 33.54 mL/g. Fick’s law can well describe the diffusion behavior of CO2 in activated carbon. The addition of a surface modifier can increase the diffusion coefficient. The diffusion of CO2 in activated carbon falls into the category of crystal diffusion. The adsorption kinetics of CO2 before and after surface modification follow the Bangham equation. During the adsorption process, δ H < 0, δ G < 0, δ S < 0. Surface modification can reduce adsorption heat and promote adsorption, and the adsorption process is dominated by physisorption.

Physicochemical synergistic adsorption of CO2 by PEI‐impregnated hierarchical porous polymers

“…It is well known that carbon capture and storage technology (CCS) is considered as the main solution to reduce CO 2 emissions and improve the atmospheric environment. Among all CO 2 capture technologies, 2,3 adsorption is widely used due to high adsorption capacity, high selectivity, low cost of equipment and operation, and high‐purity product 4–6 …”

“…1 It is well known that carbon capture and storage technology (CCS) is considered as the main solution to reduce CO 2 emissions and improve the atmospheric environment. Among all CO 2 capture technologies, 2,3 adsorption is widely used due to high adsorption capacity, high selectivity, low cost of equipment and operation, and high-purity product. [4][5][6] Based on the existing adsorption mechanism, the adsorption properties are determined by the interaction between the support and CO 2 , including the interaction force and the interaction areas.…”