In the work of (Tong et al., 2012) a chemical model with reactions
equivalent to that described here was used. Activity coefficients
were calculated using an extended Debye–Hückel expression that
included temperature dependent interaction parameters between
ion pairs, and between ions and molecular species. Literature
expressions were used for the equilibrium constants and 14
adjustable parameters were regressed to describe the interaction
parameters for a data set of 29 points. In this case the objective
function used for regression was the relative error of the CO2 loading
as a function of the CO2 partial pressure as given by Eq. (20),