Speaker: David Sedlak

THE BREN SCHOOL OF Environmental Science & Management
at the University of California, Santa Barbara

Presents

David Sedlak
Department of Civil and Environmental Engineering
University of California Berkeley


Monday, May 18, 2009
12:30 - 1:30 p.m.
Bren Hall 1414

"Oxidant Production from Iron Nanoparticles:

Mechanisms, Contaminant Transformation and Impacts on Biological Systems"

Hosted by Patricia Holden

 

Abstract

The oxidation of iron has been studied in great detail because it plays an important role in biogeochemistry and water treatment.  The oxidation of iron also has been exploited as a means of transforming pollutants by producing oxidants capable of transforming contaminants, as in Fenton’s reagent.  Despite the sustained interest in iron, our ability to use iron to improve water quality is hindered by a lack of understanding of the effect of iron speciation on reaction mechanisms.  To develop a better understanding of how speciation affects the reactions of iron, we have studied the oxidation of a suite of organic compounds by nanoparticulate zero-valent iron and ferrous iron in the presence and absence of different ligands, surfaces and catalysts.  Our results indicate that it is possible to oxidize contaminants with iron by controlling iron speciation and solution conditions in a manner that favors production of hydroxyl radical and other strong oxidants.  In biological systems, many of the reactions that result in contaminant oxidation also occur near the surfaces of cells.  In some cases, these reactions explain damage to cells observed upon exposure to iron and iron nanoparticles.  However, reactions on or near surfaces lead to different results when bacteria, viruses and human lung cells are exposed to iron in the presence of oxygen.

Biography

David Sedlak is a Professor in the Department of Civil and Environmental Engineering at the University of California at Berkeley.  His research addresses water quality engineering with a focus on trace contaminants and their fate in natural and engineered systems.  Prior to joining the faculty at UC Berkeley, Sedlak was a postdoctoral researcher at the Swiss Federal Institute for Environmental Science & Technology (EAWAG).  He received a B.S. degree for Cornell University in 1986 and a Ph.D. from the University of Wisconsin-Madison in 1992.

Dr. Sedlak has served on the Executive Committee of the UC Toxic Substances Research & Teaching Program and is on the editorial boards of Environmental Science & Technology and Water Research.  He is a recipient of the NSF CAREER award, WERF’s Paul L. Busch Award and a Fulbright Senior Scholar Fellowship. 

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