Adsorptive capture of CO2 by amine-impregnated activated carbon, pumice, and zeolite 4A

Abstract

This study provides comparative information about CO2 capture of raw and amine-impregnated micro-, meso-, and macroporous support materials. Zeolite 4A (4A), activated carbon (AC), and pumice (P) were used as micro-, meso-, and macroporous support materials, respectively, and monoethanolamine (MEA) and diethanolamine (DEA) were used as the immobilized liquid. Adsorption of CO2 from CO2-N2 mixtures (3–28%, v/v) was performed in a constant volume-variable pressure cell at 293 ± 2 K, and desorption of saturated sorbents was carried out at 373 ± 2 K. The textural properties of the porous supports have been seen to play an important role in amine loading into the pores and the mass transport of CO2 into/from the amine-loaded pores. Among the porous supports, despite its lower surface area, pumice with a macroporous backbone helped immobilization of a large amount of amine and facilitated the CO2 sorption and desorption. Amine loading increased the CO2 capture efficiencies of activated carbon, pumice, and zeolite 4A as 13.4, 19.1, and 5.4 times for MEA and 6.2, 8.8, and 4.1 times for DEA, respectively. It was found that the CO2 release rates from MEA- and DEA-impregnated 4A, AC, and P were 0.215, 0.475, and 0.556 mg CO2·g sorbent–1·min–1 and 0.242, 0.580, and 0.670 mg CO2·g sorbent–1·min–1, respectively, at 373 ± 2 K and 1 kPa. The CO2 sorption capacities of the MEA-impregnated support materials from the cyclic operation were affected negatively more than the DEA-impregnated ones and this effect increased from the microporous support material to the macroporous. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.