Thermodynamic model for solution behavior and solid-liquid equilibrium in Na-Al(III)-Fe(III)-Cr(III)-Cl-H₂O system at 25°C

Abstract

The knowledge of the thermodynamic behavior of multicomponent aqueous electrolyte systems is of main interest in geo-

A thermodynamic model for solution behavior and solid-liquid equilibrium in Na-K-Mg-Ca-Al(III)-Fe(III)-Cr(III)-Cl-H2O system from low to very high concentration at 25°C

“…The 8 th component system Na-K-Mg-Ca-Al(III)-Cr(III)-Fe(III)-Cl-H 2 O have been investigated according to the following scheme [4,5,9,12] : i) evaluation of not-concentration restricted (β 0 , β 1 , (β 2 ) and C φ ) solution parameters for all 7 chloride binary sub-systems systems (NaCl- [17] by validation of binary interaction parameters, and evaluation of new mixing interaction parameters for potassium, magnesium and calcium-, and…”

“…To describe correctly the activities for whole concentration range up to saturation in binary system FeCl 3 -H 2 O Christov [30] used extended version of Pitzer approach with 4 interaction parameters (β 0 , β 1 , β 2 ,and C φ ) and by variation additionally of 2 term in fundamental Pitzer equations [4,28,29,31]. The applicability M(III)Cl 3 -H 2 O parameters has been proved by development of solid-liquid equilibrium models for ternary and multicomponent systems of various type [5,17,20,25,26,30].…”

“…It shoud be noted that the accepted θ(K,Al) value in Christov et al [24] is much higher, compare to other θ(K,M(III)) values for K + -M 3+ common anion chloride and sulfate systems (see Table 3 in [5]). In a series of papers Christov, and Christov and co-authors developed a solid-liquid equilibrium model, which includes all M(III)-ternary subsystems within K-Mg-Al-Cl-SO 4 (θ(Na,M(III)= -0.07) is also accepted in our recent models for NaCl-AlCl 3 -H 2 O, NaCl-CrCl 3 -H 2 O, and NaCl-FeCl 3 -H 2 O systems [17]. Therefore, in this study we develop a new chloride (1-1)+(3-1) models for KCl-AlCl 3 -H 2 O (Fig.…”

“…This is why a permanent updating work must be done in order to increase the applicability of developed models, and consequently the quality of predicted results. This paper continues our series concerning parameterization of Pitzer approach based comprehensive models which can assist in the development of a complex thermodynamic database that can accurately predict the chemical behavior of aluminum Al 3+ [14,15,17,[20][21][22][23][24][25], chromium (Cr 3+ ) [5,21,23,26], chromate (CrO 4 ) [27], dichromate (Cr 2 O 7 ) [28,29], and Iron (as Fe 2+ [30]), and Fe 3+ ( [16,30] solution species and minerals in a sea-type natural fluid systems.…”

“…The main objective of this study is the development of a high accuracy thermodynamic model for solution behavior, and highly soluble sea-type chloride solids, and M(III)Cl 3 (s) (M= Al, Fe, Cr) minerals solubility in the following mixed systems: 1) KCl-AlCl 3 [5,17,30], we fully complete our model for the 8 th component system Na-K-Mg-Ca-Al(III)-Cr(III)-Fe(III)-Cl-H 2 O. Comprehensive thermodynamic models that accurately predict aluminum, chromium and iron aqueous chemistry and M(III) mineral solubilities as a function of pH, solution composition and concentration are critical for understanding many important geochemical and environmental processes involving these metals (e.g., mineral dissolution/alteration, rock formation, changes in rock permeability and fluid flow, soil formation, mass transport, toxic M(III) remediation).…”