Nanoscale And Microscale Iron Emulsions For Treating Dnapl

Chlorinated solvents in groundwater are most commonly addressed using pump and treat technology. Due to the slow dissolution of solvents from residual or pooled dense non-aqueous phase liquid (DNAPL) sources, pump and treat primarily provides containment, rather than remediation. An innovative technique that can be applied to DNAPL pools located under existing, occupied facilities, and the feasibility of using emulsified nanoscale iron particles to enhance dehalogenation of DNAPL free-phase were presented. The emulsified system consisted of a surfactant stabilized oil-in-water emulsion with the nanoscale iron particles contained within the emulsion particles. DNAPL, e.g., trichloroethylene (TCE), diffused through the oil membrane of the emulsion particle whereupon they reach the surface of an iron particle where dehalogenation takes place. More than 200 different emulsions were evaluated for TCE degradation efficiency. None of the emulsions yielded concentrations of chlorinated byproducts in solution above the detection limit. The only product that could be measured was ethylene and some small concentrations of other hydrocarbons. Ethylene exited through the micelle wall where it then entered free phase water and the gaseous headspace