Use of Oxidants to Improve Contaminant Remediation Spring Celebration Use of Oxidants to Improve Contaminant Remediation David L. Sedlak, Ph.D. sedlak@ce.berkeley.edu http://www.ce.berkeley.edu/~sedlak/

Project Team David Sedlak (CEE) Fiona Doyle (MSE) David Waite (Univ. of New South Wales) Christy Keenan Ahn Pham

Oxidative Treatment Technologies Motivation Recalcitrant polar contaminants (e.g., NDMA) Hydrophobic contaminants (e.g., PCBs) Passive treatment (e.g., As in groundwater)

Oxidative Treatment Technologies Motivation Recalcitrant polar contaminants (e.g., NDMA) Hydrophobic contaminants (e.g., PCBs) Passive treatment (e.g., As in groundwater) Limitations Requires unstable reagents (e.g., H2O2) Hydroxyl radical is unselective

Fe Nanoparticles as Reductants Currently used for contaminant reduction Zhang (2003)

Fe Nanoparticles as Oxidants Oxygen activation during Fe corrosion Fe0(s) Fe2+ 2H+ Fe0(s) Fe2+ O2 O22- H2O2 H2O Fe2+ . Fe3+ + OH- OH OH- . RH R oxid

Oxidation of Molinate by Fe Nanoparticles air Joo et al. (2004) O2

Oxidation of As(III) by Fe As(III) oxidation and As(V) adsorption Leupin & Hug (2005)

Oxidation of As(III) by Fe Selective As(III) oxidation Hug and Leupin (2003)

Oxidative Remediation with Iron Fe can convert O2 into a powerful oxidant Potential for selective oxidation on surface Potential applications Passive treatment barriers Soil and groundwater treatment Drinking water treatment