Transport and kinetic studies to characterize reactive and nonreactive sites on granular iron.

To better understand controls on observed trichloroethene (TCE) reaction rates in granular iron permeable reactive barriers, column experiments were conducted with different iron loadings. Using a reactive transport model and the Kinetic Iron Model (KIM), unique estimates of Langmuir sorption parameters for both the nonreactive and reactive sites, and a rate constant for TCE reduction on the iron surface provides new insights into the character of granular iron that determines overall reactivity. Nonreactive isotherms found in this work compared well with literature isotherms, and it was also found that for TCE and Connelly iron, only about 2% of sorption occurred to reactive sites, in agreement with earlier work by others. Thus, the KIM parameters were found to be relevant and useful under the conditions of these experiments.