Tuesday, April 7, 2009

Chemical Remediation of Contaminants in Water and Soil using Fenton Advanced Oxidation Systems

As part of the requirements for FOR 496/797 Environmental Career Strategies for Women, students share the responsiblity for reporting on the speakers in the Women in Environmental Professions Speaker Series.  The following was prepared by Shavaun Jenkins and Christina Quinn.
Dr. Ann Lemley, a Professor in the College of Human Ecology at Cornell University, concluded SUNY ESF’s 2009 Women in Scientific and Environmental Professions Speaker Series with a talk entitled Chemical Remediation of Contaminants in Water and Soil using Fenton Advanced Oxidation Systems on April 7. The Department of Chemistry and the ESF Women’s Caucus co-sponsored the seminar.
Dr. Lemley discussed her current research concerning the use of chemical means for the degradation of contaminants in water and soil. Contaminated soils pose potentially serious threats to surface and ground water quality, particularly when contaminant concentrations are high due to accidental spills or discharges. Therefore, the goal of her work is to develop a practical system for the removal or treatment of contaminants, including pesticides, pharmaceuticals, and other organics, from water and soil systems.
Beginning with a brief introduction into the background of pesticide contamination and the complications associated with its remediation, Dr. Lemley described how advanced oxidation processes (AOPs) offer fast and effective techniques for remediation. Specifically, her lab focuses on the application of Fenton reactions (Fe2+ + H2O2 àFe3+ + OH- + *OH) to degrade contaminants in water and soil/clay slurries through an indirect electrochemical method, known as Anodic Fenton treatment (AFT), that generates Fe2+ via electrolysis. This treatment offers several advantages including the avoidance of problems with hygroscopic salts, reducing the need for reactions at extreme pH’s, and the ability to control the release of reagents and measure the *OH radical reaction rates.
            Within Dr. Lemley’s research group, an AFT kinetic model has been developed and, using competitive kinetics, optimized to allow for the measure of concentrations of coexisting contaminants. Furthermore, this model has been revised to accommodate nitrogen-containing pesticides (tricosenes).  Dr. Lemley concluded her presentation with an illustration of the application of the AFT kinetic model in soil slurries and layered clays. Through the use of X-ray diffraction, the adsorption of several probe chemicals, including mecoprop (anionic), carbaryl (neutral) and paraquat (cationic) was measured along with their subsequent degradation rate by AFT. While anionic and neutral chemicals can be effectively and completely degraded by AFT, the removal of cationic chemicals in soil/clay may prove more difficult due to strong electrochemical interactions. Future research will be focused on developing electrochemical systems for different applied situations and the study of a variety of other contaminants, including animals antibiotics, and their rate of degradation and subsequent degradation products.
Dr. Lemley received her B.A. in Chemistry and Education from St. John’s University, and both her Master’s and Ph.D. in Chemistry from Cornell University.  Currently, Dr. Lemley is a Professor and Chair of the Department of Fiber Science & Apparel Design, working in the Field of Environmental Toxicology, at Cornell University. She is also on the Editorial Board of several journals (including the Bulletin of Environmental Contamination and Toxicology, Journal of Agricultural and Food Chemistry, and Journal of Environmental Science and Health, Part A) and active with the NYSTAR Center for Environmental Quality centered at Syracuse University.

For more information about events sponsored by the ESF Women’s Caucus, please visit http://www.esf.edu/womenscaucus.

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