Thermodynamics of NaHCO₃ decomposition during Na₂CO₃-based CO₂ capture

Amine-basedcarbon-capture technologies have been shown to be energetically expensive and to cause significant environmental and epidemiological impacts due to their volatility. Bicarbonate formation from carbon dioxide's reaction with water has been suggested as an effective alternative for capturing CO₂; however, the thermodynamics of this reaction are not well understood. This study experimentally determined the equilibrium constant of sodium bicarbonate (NaHCO₃) decomposition to sodium, water, and carbon dioxide; the study also compared the equilibrium constant to theoretical calculations. Using a combination of experimentation and thermodynamic relationships, the unitless equilibrium constants of the forward and reverse reactions were calculated accurately (error <±9% and <±4%, respectively). Equilibrium data were calculated using enthalpy and entropy values of each component of NaHCO₃ decomposition at temperatures ranging from 25 to 155°C respectively. These results offer more data essential to optimizing NaHCO₃ use in environmentally friendly next-generation CO₂-capture technologies.