Competitive Sorption and Displacement of Hydrophobic Organic Contaminants in Saturated Subsurface Soil Systems

Abstract

The sorption of tetrachloroethylene and trichlorobenzene by a subsurface soil that exhibits moderately nonlinear sorption isotherms for each solute was found to be strongly competitive, while that by a soil for which both solutes exhibit more linear sorption isotherms was essentially additive. The isotherm nonlinearity and competitive sorption observed in the former case suggest that a greater fraction of the sorption by that soil occurred on or within tightly ordered or condensed organic matrices rather than within more amorphous soil organic matter. Ideal adsorbed solution theory was used in conjunction with a Freundlich isotherm in a dual-domain model to characterize mathematically the sorption behavior of these two soils in column-type reactor systems. Model parameters obtained independently from breakthrough curves for single-solute systems were used to predict breakthrough curves for bisolute systems. The results demonstrate that (1) even moderate isotherm nonlinearity can affect breakthrough curve behavior in single-solute systems, and (2) the effects of isotherm nonlinearity on solute breakthrough are significantly increased by the additional manifestation of competitive effects in bisolute systems. erties of these subsurface soils have been provided earlier byWeber et al. [ 1992]. Tetrachloroethylene (TTCE) and 1,2,4-trichlorobenzene (TCB) were the solutes chosen for study. Working solutions were prepared by dissolving these solutes in methanol and 3571

Enhancing the Bioavailability of Organic Compounds Sequestered in Soil and Aquifer Solids

“…McGinley et al [21] observed competitive effects in a diagenetically old soil but not in an immature soil rich in amorphous organic matter.…”

Simultaneous sorption of phosphate and phenanthrene to inorgano–organo-bentonite from water

“…It is commonly accepted that sorption of organic compounds into organoclay are partitioning (dissolution) [35], and the characteristic of sorption isotherm is linear [36]. Moreover, parti- tioning shows no competition between solutes.…”

Sorption Behaviour of Phenols on Natural Sandy Aquifer Material during Flow‐through Column Experiments: The Effect of pH

“…In order to model these transport processes sorption equilibrium parameters are required. In the past, most of the published equilibrium studies were focused upon neutral organic substances, e.g., PAHs [1,2], polychlorinated biphenyls [3,4], monocyclic aromatic hydrocarbons [5,6], chlorinated benzenes [7], chlorinated aliphatic hydrocarbons [5Ϫ8].…”