Reactivity of Various Zero Valent Irons: Reduction of Trichloroethylene Saving the World! Lauren Vice, Jim Nurmi, John Schneider, Paul Tratnyek Department of Environmental and Biomolecular Systems OGI School of Science and Engineering Oregon Health & Science University ARS Technologies

Chlorinated Solvents and Possible Remediation Chlorinated Solvents are widely used and manufactured –1980 = 121,000 metric tons of TCE produced Suspected carcinogens & harmful to aquatic organisms Natural Remediation Permeable Reactive Barriers (PRB’s) –Reduce chlorinated solvents 1. 1 Blowes, David (2007, May). In Situ. Retrieved August 15, 2008, from In Situ Treatment of Metals and other Inorganic Contaminants in Groundwater using Permeable Reactive Barriers: Treatability Testing Web site:

Primary Objective Determine rate of TCE disappearance (k obs ) with various ARS irons, and Measure presence and rate of appearance of daughter products. Proposed pathway TCE DCE VC ethene Ethylene chloride ethane

Batch Experiments HP 5890 Gas Chromatographer with DB 624 Column

TCE Degradation Initial TCE spike,.0523 M

Various Rate Constants Ironk Obs (min -1 ) k Mass (min -1 g -1 ) k SA (L m -2 min -1 ) Sponge (5g) 1.367E E E-04 Cast (5g) 2.044E E E-05 Ultra-Fine (5g) E E E-05 HSA (20g) 2.536E E E-06 QMP (20g) E E E-05

Comparing Various Rate Constants for both CT and TCE Carbon Tetrachloride Trichloroethylene

Conclusion With out major research on daughter products of all five ARS iron types no clear conclusion can be made on which of the five irons is most efficient at degrading chlorinated solvents Further data must be collected

Suggestions for Future Research Further study of product peaks, such as those seen with High- Sulfur Atomized Iron Study of pH effects on degradation Look at longevity of various irons degradation abilities with chlorinated solvents

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