Hydrogen Peroxide Persistence in the Presence of Aquifer Materials

Abstract

In situ chemical oxidation using hydrogen peroxide for groundwater remediation has received a great deal of attention over the last 15 years. A comprehensive investigation that focused on the interaction between hydrogen peroxide and eight aquifer materials was performed using both batch and column experiments. The results from the batch experiments indicated that the decomposition of hydrogen peroxide in the presence of various aquifer materials followed a first-order rate law, and was strongly affected by the content of amorphous transition metals. The exposure of the aquifer solids to hydrogen peroxide for 14 days indicated that not all forms of natural organic matter (NOM) contributed to the observed decomposition. Multiple linear regression analysis was used to generate two potentially useful predictive decomposition rate coefficient relationships based on the various aquifers’ material characteristics. Column experiments were conducted with five representative aquifer materials to complement and expand the findings from the batch experiments. As expected the decomposition rate coefficients were higher in the column experiments relative to the batch experiments due to the larger solids mass to solution volume ratio. Attempts to simulate the column observations indicated that dissolution and transport of metals from aquifer solids may play an important role in hydrogen peroxide persistence in some subsurface environments.