Faculty Mentors:
Dr. Stephen Mezyk (Chemistry & Biochemistry)
Research Interests:
Understanding the kinetics and mechanisms of reaction of radicals has been a focus of my research for many years now. The applications of this research are extremely widespread, but at present two of our major projects are:
1) The removal of dangerous chemicals from drinking water. This area of research has been investigating the use of oxidizing hydroxyl radicals (·OH) and reducing hydrated electrons (e-aq) to destroy unwanted chemicals in drinking water. The goal of this work is to identify the classes of chemicals that can be readily treated using these radicals, and then optimizing the conditions for this chemistry. Currently our investigations are focused upon the removal of different classes of carcinogens, pharmaceuticals, pesticides/herbicides and their residues, as well as by-product chemicals formed in the water purification processes.
2) Understanding the mechanisms of carcinogenesis. The major focus for us in this area is the chemical class of nitrosamines (R1R2N-NO) which have been proven to be carcinogenic, mutagenic, and teratogenic. Nitrosamines are everywhere in our world, found in many food and beverage products, especially after fermenatation or cooking, and notably in cigarette smoke. However, the radical-based action of these chemicals, especially under biological conditions, has not been well characterized. Presently, we are studying the formation and subsequent reactions of nitrosamine radical species, especially with the biologically significant superoxide and carbonate radicals.
Most of the kinetic measurements required for this work are performed at the University of Notre Dame Radiation Laboratory, requiring us to travel to this facility several times a year. Stable product studies (for mechanisms) are performed here at CSULB.Laboratory refereed publications for last two years (* indicates CSULB student):
1. S.P. Mezyk, D. Ewing*, J.J. Kiddle, W.J. Cooper, and K.P. Madden, “Free Radical Oxidation and Reduction of Nitrosamines and Nitramines in Aqueous Solution”, accepted for publication J. Phys. Chem. A (2006).
2. S.P. Mezyk, T. Helgeson*, S.K. Cole, W.J. Cooper, R.V.Fox, P.R. Gardinali, B.J. Mincher, Free Radical Chemistry of Disinfection-Byproducts. 1. Kinetics of hydrated electron and hydroxyl radical reactions with halonitromethanes in water, J. Phys. Chem. A, 110, 2176-2180, (2006).
3. S.P. Mezyk, and D. M. Bartels, Rate Constant and Activation Energy Measurement for the Reaction of Atomic Hydrogen with Azide and Thiocyanate in Aqueous Solution, J. Phys. Chem. A, 109, 11823-11827, (2005).
4. Xu, T.; Cai, Y.; O’Shea, K.E.; Mezyk, S.P., The Roles of Hydroxyl Radical, Superoxide Anion Radical and Hydrogen Peroxide in the Oxidation of Arsenite by Ultrasonic Irradiation. ACS Symposium Series 915: Advances in Arsenic Research: Integration of Experimental and Observational Studies and Implications for Mitigation, O'Day, P.A.; Vlassopoulos, D.; Meng, X.; Benning, L.G., Eds. 333-343, (2005).
5. S.P. Mezyk, W.J. Cooper, and K.P. Madden. Fundamental Radiolysis Studies of NDMA (N,N-dimethylnitrosoamine): Kinetic and Mechanistic Relevance to AOT Destruction. Photocatalytic and Advanced Oxidation Processes for Treatment of Air, Water, Soil and Surfaces, Ollis, D. and Al-Ekabi, H. (Eds). University of Western Ontario Press, p. 324-331, (2005).
6. S.K. Cole, W.J. Cooper, B.J. Mincher, R.V. Fox, P.R. Gardinali, K. E. O’Shea, and S.P. Mezyk. The Radiation Chemistry and Free Radical Treatment of Bromonitromethane. Photocatalytic and Advanced Oxidation Processes for Treatment of Air, Water, Soil and Surfaces, Ollis, D. and Al-Ekabi, H. (Eds). University of Western Ontario Press, p. 311-318, (2005).
7. K.E. O’Shea, D.-K. Kim, S.P. Mezyk, W.J. Cooper, Comparison of the Radiolytic, Photocatalytic, and Sonolytic Induced Degradation of Gasoline Oxygenates. Photocatalytic and Advanced Oxidation Processes for Treatment of Air, Water, Soil and Surfaces, Ollis, D. and Al-Ekabi, H. (Eds). University of Western Ontario Press, p. 303-310, (2005).
8. J. Kiddle and S.P. Mezyk, Reductive Destruction of Chemical Warfare Agent Simulants in Water, J. Phys. Chem. B., 108, 9568-9570 (2004).
9. S.P. Mezyk, W.J. Cooper, K.P. Madden, D.M. Bartels, Free Radical Destruction of N-Nitrosodimethylamine (NDMA) in Water, Environ. Sci. Technol., 38, 3161-3167, (2004).
10. S.P. Mezyk, J. Jones*, W.J. Cooper, T. Tobien, T., M.G. Nickelsen, J.W. Adams, K.E. O’Shea, D.M. Bartels, J.F. Wishart, P.M. Tornatore, K.S. Newman, K. Gregoire, and D.J. Weidman, Radiation Chemistry of Methyl-tert-Butyl Ether (MTBE) in Aqueous Solution, Environ. Sci. Technol., 38, 3994-4001, (2004).
Office location:
PH2-019
Lab:
PH2- 014
Campus Phone:
562-985-4649
