Nonideal equilibrium dissolution of trichloroethene from a decane-based nonaqueous phase liquid mixture: Experimental and modeling investigation - art. no. 1097

摘要

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 greater than or equal toX(TCE)(N)less than or equal to0.1). 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 (gamma(TCE)(N)), increased nonlinearly as the X-TCE(N) decreased. The gamma(TCE)(N) approached 6 at X-TCE(N) = 0.0001. The UNIFAC method greatly underpredicts the gamma(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. References: 42