Analysis of the CO₂Chemisorption in Li₅FeO₄, a New High Temperature CO₂Captor Material. Effect of the CO₂and O₂Partial Pressures

Abstract

Pentalithium ferrite (Li 5 FeO 4 ) was tested as possible CO 2 captor, both by theoretical calculations and experimental measurements. The pristine Li 5 FeO 4 compound with orthorhombic structure was synthesized via solid-state reaction and it was structural and microstructurally characterized. Later, sample was heat-treated at temperatures from room temperature to 900 °C under different CO 2 or CO 2 –O 2 atmospheres. Li 5 FeO 4 exhibits excellent CO 2 chemisorption abilities with a capture capacity about 12.9 mmol/g, which is outstanding in comparison to other previously reported ceramic captors. This material is able to react with CO 2 from 200 °C to approximately 715 °C showing a high kinetic of reaction even at CO 2 partial pressure values as low as 0.2. Additionally, results suggest that oxygen addition does enhance the CO 2 chemisorption on Li 5 FeO 4 at temperatures below 700 °C, although oxygen addition seems to favor the desorption process at higher temperatures.