Refined electrolyte‐NRTL model: Activity coefficient expressions for application to multi‐electrolyte systems

Abstract

in Wiley InterScience (www.interscience.wiley.com).The influence of simplifying assumptions of the electrolyte-nonrandom two-liquid (NRTL) model in the derivation of activity coefficient expressions as applied to multi-electrolyte systems is critically examined. A rigorous and thermodynamically consistent formulation for the activity coefficients is developed, in which the simplifying assumption of holding ionic-charge fraction quantities constant in the derivation of activity coefficient expressions is removed. The refined activity coefficient formulation possesses stronger theoretical properties and practical superiority that is demonstrated through a case study representing the thermodynamic properties and speciation of dilute to concentrated aqueous sulfuric acid solutions at ambient conditions. In this case study phenomena, such as hydration, ion pairing, and partial dissociation are all taken into account. The overall result of this study is a consistent, analytically derived, short-range interaction contribution formulation for the electrolyte-NRTL activity coefficients and a very accurate representation of aqueous sulfuric acid solutions at ambient conditions at concentrations up to 50 molal. 2008 American Institute of Chemical Engineers AIChE J, 54: [1608][1609][1610][1611][1612][1613][1614][1615][1616][1617][1618][1619][1620][1621][1622][1623][1624] 2008 Keywords: electrolyte thermodynamics, electrolyte-NRTL, ionic activity coefficients, multi-electrolyte solutions, mixing of electrolytes, aqueous sulfuric acid IntroductionThe electrolyte-nonrandom two-liquid (NRTL) model 1 has been extensively applied to represent thermodynamic properties of various electrolyte systems. Examples include mean ionic activity coefficients of aqueous strong electrolytes 1,2 and aqueous organic electrolytes, 3 phase behavior of weak electrolytes, 1 strong acids, 4 mixed-solvent electrolytes, 5 and so forth. The main reasons for its wide acceptance and application are the incorporation of semi-fundamental chemical theories such as the NRTL model for the simulation of local Correspondence concerning this article should be addressed to G. M. Bollas at bollas@mit.edu. *Disclaimer: This paper was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any age...

Evaporation of sulfate aerosols at low relative humidity

“…Since AIOMFAC does not consider inorganic nonelectrolyte compounds like H 2 SO 4 and SO 3 we implement additionally to this the symmetric electrolyte-NonRandom Two-Liquid (eNRTL) activity coefficient model (Bollas et al, 2008;Song and Chen, 2009) which is optimised for the H 2 SO 4 -H 2 O-SO 3 systems by Que et al (2011). In this work we use the regressed eNRTL binary interaction parameters from Que et al (2011).…”

Modelling of gas clathrate hydrate equilibria using the electrolyte non-random two-liquid (eNRTL) model

“…(26) and ( are composition dependent quantities which are derived by means of the following relations [15,23] ( ) [15,23] …”

“…Besides, numerous semi-empirical excess Gibbs energy models have been proposed [15], as e.g. the model of Bromley [16], the ion-interaction model of Pitzer [17,18], the model of Cruz and Renon [19], the eNRTL-model of Chen et al [15,[20][21][22][23], the LIQUAC-model of Li et al [24] and the MSA-model of Papaiconomou et al [25].…”

“…In this preliminary study the aim is to test the suitability of the model to describe systems with conventional gas hydrate phases in the presence of electrolytes. Therefore, a Java implementation of both the previous [21] and the updated version of the single-solvent multicomponent eNRTL-model [23] was created initially. After having thoroughly tested the correctness of the eNRTL-code, the programme was incorporated into our previously existing in-house programme for modelling H-L w -G-phase equilibria.…”

Enhanced Selectivity of the Separation of CO2from N2during Crystallization of Semi-Clathrates from Quaternary Ammonium Solutions

“…In this work, a modification of the model approach of Paricaud (2011) is used in which in contrast to the use of the SAFT-VRE equation of state (Galindo et al, 1999) the electrolyte NRTL model (eNRTL-model) (Chen et al, 1982;Chen and Evans, 1986;Bollas et al, 2008) is incorporated into the model to describe the liquid phase non-idealities in presence of TBAB In Equation (14), T…”