Main content area

Thermodynamics of NaHCO3 decomposition during Na2CO3-based CO2 capture

Toan, Sam, O'Dell, William, Russell, Christopher K., Zhao, Sun, Lai, Qinghua, Song, Huiping, Zhao, Ying, Fan, Maohong
Journal of environmental sciences (China) 2019 v.78 pp. 74-80
carbon dioxide, enthalpy, entropy, sodium, sodium bicarbonate, temperature
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.