posted on 2019-02-06, 17:33authored byQiaoxin Wang, Zhibao Li
In
this work, the solubility behavior of salts NaCl and NH4Cl was investigated in aqueous diethanolamine (DEA) solution
by varying both temperature and the solvent composition. DEA has been
prevalently used in the postcombustion process to capture CO2, but a limited amount of references can be found pertaining to any
solid–liquid system containing DEA. It was experimentally determined
that the solubility of NaCl decreases, whereas the solubility of NH4Cl increases with the addition of DEA (x′DEA = 0–0.2). The solubility of both salts increases
if temperature is raised from 283 to 353 K. The common-ion effect
was examined for the quaternary system when both salts are present
in the solution. By the regression of solubility data with the Mixed
Solvent Electrolyte model, we proved that readjusting the middle-range
interaction parameters between Cl–-DEA and DEAH+-Cl– would lower the relative deviation
(within 5%) for each proposed ternary system. A comprehensive chemical
model was further constructed based on the newly adjusted interaction
parameters, provided to further analyze system equilibria, as well
as the activity coefficients for aqueous electrolytes.