Extended UNIQUAC model for correlation and prediction of vapour–liquid–solid equilibria in aqueous salt systems containing non-electrolytes. Part A. Methanol–water–salt systems

Iliuta, Maria C.; Thomsen, Kaj; Rasmussen, Peter

doi:10.1016/s0009-2509(99)00534-5

Cited by 96 publications

(99 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Instead of using mixing rules to estimate the density and dielectric constant of the solvent mixture, we use water properties for all solvent components. Similar assumptions were made for the LR part of other mixed solvent models (Iliuta et al, 2000). With this constraint, the corresponding LR activity coefficient expressions for the solvents γ LR,(x) s and the ions γ LR,(x),∞ i are:…”

Section: Long-range Contributionmentioning

confidence: 97%

A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

et al. 2008

View full text Add to dashboard Cite

Abstract. Tropospheric aerosols contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. Interactions between these substances in liquid mixtures lead to discrepancies from ideal thermodynamic behaviour. By means of activity coefficients, non-ideal behaviour can be taken into account. We present here a thermodynamic model named AIOMFAC (Aerosol InorganicOrganic Mixtures Functional groups Activity Coefficients) that is able to calculate activity coefficients covering inorganic, organic, and organic-inorganic interactions in aqueous solutions over a wide concentration range. This model is based on the activity coefficient model LIFAC by Yan et al. (1999) that we modified and reparametrised to better describe atmospherically relevant conditions and mixture compositions. Focusing on atmospheric applications we considered H + , Li + , Na + , K + , NH 4 as cations and anions and a wide range of alcohols/polyols composed of the functional groups CH n and OH as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are well represented up to high ionic strength. Most notably, a semi-empirical middle-range parametrisation of direct organic-inorganic interactions in alcohol+water+salt solutions strongly improves the agreement between experimental and modelled activity coefficients. At room temperature, this novel thermodynamic model offers the possibility to compute equilibrium relative humidities, gas/particle partitioning and liquid-liquid phase separations with high accuracy. In further studies, other organic functional groups will be introduced. The model framework is not restricted to specific ions or organic compounds and is therefore also applicable for other research topics.

show abstract

Section: Long-range Contributionmentioning

confidence: 97%

A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

et al. 2008

View full text Add to dashboard Cite

show abstract

“…In a real mixture, solvents have densities and dielectric properties different from those of pure water. For this reason, these simplifications of the LR part were made in other mixed solvent models in chemical engineering and technical chemistry applications (see Iliuta et al, 2000). The uncertainties that occurred due to the adopted assumptions to derive the LR and SR activity coefficients with respect to approximations of parameters, were described in the semi-empirical SR part as in the original AIOMFAC (Zuend et al, 2008).…”

Section: The Long-range Contributionmentioning

confidence: 99%

Treatment of non-ideality in the SPACCIM multiphase model – Part 1: Model development

et al. 2016

View full text Add to dashboard Cite

Abstract. Ambient tropospheric deliquesced particles generally comprise a complex mixture of electrolytes, organic compounds, and water. Dynamic modeling of physical and chemical processes in this complex matrix is challenging. Thus, up-to-date multiphase chemistry models generally do not consider non-ideal solution effects. Therefore, the present study was aimed at presenting further development of the SPACCIM (Spectral Aerosol Cloud Chemistry Interaction Model) through treatment of solution non-ideality, which has not been considered before. The present paper firstly describes the model developments including (i) the implementation of solution non-ideality in aqueous-phase reaction kinetics in the SPACCIM framework, (ii) the advancements in the coupling scheme of microphysics and multiphase chemistry and (iii) the required adjustments of the numerical schemes, especially in the sparse linear solver and the calculation of the Jacobian. Secondly, results of sensitivity investigations are outlined, aiming at the evaluation of different activity coefficient modules and the examination of the contributions of different intermolecular forces to the overall activity coefficients. Finally, first results obtained with the new model framework are presented.The SPACCIM parcel model was developed and, so far, applied for the description of aerosol-cloud interactions. To advance SPACCIM also for modeling physical and chemical processes in deliquesced particles, the solution non-ideality has to be taken into account by utilizing activities in reaction terms instead of aqueous concentrations. The main goal of the extended approach was to provide appropriate activity coefficients for solved species. Therefore, an activity coefficient module was incorporated into the kinetic model framework of SPACCIM. Based on an intercomparison of different activity coefficient models and the comparison with experimental data, the AIOMFAC approach was implemented and extended by additional interaction parameters from the literature for mixed organic-inorganic systems. Moreover, the performance and the capability of the applied activity coefficient module were evaluated by means of water activity measurements, literature data and results of other activity coefficient models. Comprehensive comparison studies showed that the SpactMod (SPACCIM activity coefficient module) is valuable for predicting the thermodynamic behavior of complex mixtures of multicomponent atmospheric aerosol particles. First simulations with a detailed chemical mechanism have demonstrated the applicability of SPACCIM-SpactMod. The simulations indicate that the treatment of solution non-ideality might be needed for modeling multiphase chemistry processes in deliquesced particles. The modeled activity coefficients imply that chemical reaction fluxes of chemical processes in deliquesced particles can be both decreased and increased depending on the particular species involved in the reactions. For key ions, activity coefficients on the order of 0.1-0.8 and a strong dependenc...

show abstract

“…More information can be found in the literature [15][16][17]. Extended UNIQUAC volume and surface area parameters and interaction parameters are reported in Table 2, 3 and 4 [18].…”

Section: Calculations Of Phase Diagram By Extended Uni-quac Modelmentioning

confidence: 99%

Representation of material balance for fractional crystallization of reciprocal salt pair Systems: KNO<sub>3</sub> production case study

Ghader

Shadravan

Mansouri

et al. 2010

Chem. Eng. Res. Bull.

View full text Add to dashboard Cite

Abstract:In this paper, determination of material balance for reciprocal salt pair systems is considered and special case of KNO 3 production is solved. A scheme is presented for calculation of material balance which is based on the conservation of ions and water. Material balance requires equilibrium composition and phase diagram of solid-liquid equilibria that is calculated by extended UNIQUAC thermodynamic model.

show abstract

Extended UNIQUAC model for correlation and prediction of vapour–liquid–solid equilibria in aqueous salt systems containing non-electrolytes. Part A. Methanol–water–salt systems

Cited by 96 publications

References 46 publications

A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

Treatment of non-ideality in the SPACCIM multiphase model – Part 1: Model development

Representation of material balance for fractional crystallization of reciprocal salt pair Systems: KNO<sub>3</sub> production case study

Contact Info

Product

Resources

About