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Revisiting electrolyte thermodynamic models: Insights from molecular simulations
Author(s) -
Hossain Nazir,
Ravichandran Ashwin,
Khare Rajesh,
Chen ChauChyun
Publication year - 2018
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.16327
Subject(s) - activity coefficient , thermodynamics , electrolyte , supersaturation , chemistry , aqueous solution , osmotic coefficient , ionic strength , ionic liquid , ionic bonding , ion , physics , organic chemistry , electrode , catalysis
Pitzer and electrolyte nonrandom two‐liquid (eNRTL) models are the two most widely used electrolyte thermodynamic models. For aqueous sodium chloride (NaCl) solution, both models correlate the experimental mean ionic activity coefficient ( γ ± ) data satisfactorily up to salt saturation concentration, that is, ionic strength around 6 m. However, beyond 6 m, the model extrapolations deviate significantly and diverge from each other. We examine this divergence by calculating the mean ionic activity coefficient over a wide range of concentration based on molecular simulations and Kirkwood–Buff theory. The asymptotic behavior of the activity coefficient predicted by the eNRTL model is consistent with the molecular simulation results and supersaturation experimental data. © 2018 American Institute of Chemical Engineers AIChE J , 64: 3728–3734, 2018