Optimizing CaO-based CO₂ adsorption: Impact of operating parameters

CaO-based adsorbents present a promising approach for industrial CO₂ emissions reduction. This study systematically investigates the influence of adsorption temperature, adsorbent mass, CO₂ concentration, and flow rate on CO₂ capture efficiency using commercial CaO via thermogravimetric analysis (TGA). Optimal adsorption performance, achieving a capacity of 0.62 g/g and a rate exceeding 0.14 g/g/min, was observed at 750°C, 7 mg mass, 20% CO₂, and 20 mL/min flow. Characterization (SEM, BET, and FTIR) indicated that 750°C preserved a hierarchical pore structure (24.64 m²/g surface area, 0.1026 cm³/g pore volume, and 7.08 nm average pore size), mitigating sintering and pore blockage while confining carbonation to surface layers. Kinetic modeling confirmed chemisorption dominance (pseudo-second-order). These findings elucidate fundamental mass/heat transfer limitations, supporting the development of enhanced CaO-based carbon capture, utilization, and storage (CCUS) technologies.