Effect of Reaction Parameters on CO₂ Absorption from Biogas Using CaO Sorbent Prepared from Waste Chicken Eggshell

Abstract

This study provides an efficient and straightforward approach to eliminate carbon dioxide (CO2) by absorption using a calcium oxide (CaO) sorbent derived from chicken eggshells. The sorbent concentration, stirring speed, and contact time were varied. The optimal condition for CO2 removal was a 10% calcium hydroxide (Ca­(OH)2) suspension at 600 rpm with 20 min interaction. This optimum condition conferred the ever-highest absorption (98.71%) of CO2 through Ca­(OH)2 suspensions from eggshell-derived CaO. X-ray diffraction was used to identify crystallographic phases and optimum conditions revealed calcium carbonate (CaCO3) formation with the highest intensity, Fourier transform infrared spectroscopy revealed peaks for the carbonate (CO3 2–) group, field emission scanning electron microscopy was used to investigate the morphological and structural properties of the sorbent before and after CO2 absorption, and thermogravimetric analysis was performed to understand the reaction mechanism. According to the kinetic analysis, the sorbent can be fully decomposed with a minimum activation energy (E a) of 89.09 kJ/mol.

In Situ Capture and Conversion of CO2 to CO Using CaZrO3 Promoted Fe–CaO Dual-Functional Material

“…To further elucidate the activities of Fe–CaO catalysts with and without the CaZrO 3 support, kinetic studies were conducted. The experimental data were employed to model the carbonation reaction using a zero-order kinetics framework, , enhancing the understanding of CO 2 desorption in FC and 10FCZ–5 systems. The apparent activation energy ( E a ) estimated from the Arrhenius plots of CO 2 to CO conversion rates also suggested the optimal CO 2 activation capacity of the CaZrO 3 -promoted Fe–CaO catalyst (Figure ).…”