Nonideal equilibrium dissolution of trichloroethene from a decane‐based nonaqueous phase liquid mixture: Experimental and modeling investigation

Abstract

[1] Batch equilibrium solubility studies were conducted to examine the solubilization behavior of a chlorinated solvent, trichloroethene (TCE), from a fuel-based nonaqueous phase liquid (NAPL) mixture. An alkane (n-decane) was used as a model compound because it is often a primary compound in jet fuel. The NAPL phase mole fractions of the chlorinated solvent in the mixture (X TCE N ) that were investigated are typical of in situ values found at industrial and military waste sites (0.0001 ! X TCE N 0.1). The measured aqueous concentrations of TCE were essentially equal to the concentrations predicted with ideal dissolution theory (Raoult's law) at X TCE N values near 0.1. However, the ratio of the measured concentration to the ideal concentration, or the NAPL phase activity coefficient (g N TCE ), increased nonlinearly as the X TCE N decreased. The g TCE N approached 6 at X TCE N = 0.0001. The UNIFAC method greatly underpredicts the g TCE N in this surrogate fuel. A NAPL-mixture equilibrium-dissolution model was developed that incorporates the observed nonideal dissolution. This model indicates that nonideal NAPL dissolution is 4 times faster than ideal dissolution for a hypothetical NAPL mixture with an initial X TCE N = 0.001. The magnitude of this effect becomes more important as the initial value of the X TCE N is decreased.

Dissolution, cyclodextrin-enhanced solubilization, and mass removal of an ideal multicomponent organic liquid

“…Many organic liquids are comprised of multiple compounds, and solubilization of multicomponent organic liquids may be complicated by nonideal behavior (e.g., Rostad et al, 1985; Borden and Kao, 1992; Chen et al, 1994; Lesage and Brown, 1994; Whelan et al, 1994; Adeel et al, 1996; Mukherji et al, 1997; McCray and Dugan, 2002, Burris et al, 2006). Previous research evaluating ESA applications has focused primarily on factors of mobilization and solubilization, with few investigations of organic liquid compositional impacts (Khachikian and Harmon, 2000; Oostrom et al, 2006).…”

Scenario-based modelling of mass transfer mechanisms at a petroleum contaminated field site-numerical implications

“…It is observed that depending on the initial composition and spilled volume, the methodology for estimating effective solubility may vary considerably (Borden and Piwoni, 1992;Feenstra, 1997;Frind et al, 1999;McCray and Dugan, 2002). For the present scenario considering initial spilled volume and initial composition, change in Sn with change in mole fraction of each component can be estimated as given by Vasudevan et al (2014a).…”

“…Since the spilled gasoline fuel contains large number of aliphatic, aromatic and polycyclic aromatic hydrocarbon (PAH) compounds, the estimation of effective solubility as explained by Raoult's law seemed to be inadequate to represent the actual partitioning behaviour, which largely depends on the molecular interactions (Peters et al, 1999). Deviations from ideal behaviour (when activity coefficients deviating from unity) can be due to many reasons, including chemical heterogeneity of the components of the mixture and their respective molar volumes which are not incorporated into the common application of Raoult's law (McCray and Dugan, 2002;Lekmine et al, 2014). It is also important to determine the combined effect of sorption and biodegradation which can remove the dissolved organic compounds, thus improving the source clean-up strategies (Couto and Malta, 2008;Natarajan and Suresh Kumar, 2010).…”

Dissolution of a multicomponent DNAPL pool in an experimental aquifer

“…For a dissolving multicomponent NAPL pool, the equilibrium solubility of each component varies with time because the mole fraction and the nonaqueous phase activity coefficient of each component changes as the pool composition changes [27,28]. Therefore, accounting for temporal changes in equilibrium solubility is essential for accurate analysis and prediction on the dissolution behavior of a multicomponent NAPL pool.…”