Dr. Stephen Mezyk (Chemistry & Biochemistry)
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):
S.K. Cole, W.J. Cooper, R.V. Fox, P.R. Gardinali, S.P. Mezyk, B.J. Mincher and K.E. O’Shea Free Radical Chemistry of Disinfection Byproducts 2. Rate Constants and Degradation Mechanisms of Trichloronitromethane (Chloropicrin), Environ. Sci. Technol. 41, 863-869 (2007).
P. Westerhoff, S.P. Mezyk, W.J. Cooper, and D. Minakata, Electron Pulse Radiolysis Determination of Hydroxyl Radical Rate Constants with Suwannee River Fulvic Acid and Other Dissolved Organic Matter Isolates, Environ. Sci. Technol. 41, 4640-4646 (2007).
N.A. Landsman*, K.L. Swancutt*, C.N. Bradford*, C.R. Cox*, J.J. Kiddle, and S.P. Mezyk, Free Radical Chemistry of Advanced Oxidation Process Removal of Nitrosamines in Water, Env. Sci. Technol., 41, 5818-5823 (2007).
S.P. Mezyk, T. J. Neubauer*, W.J. Cooper, and J.R. Peller, Free-Radical-Induced Oxidative and Reductive Degradation of Sulfa Drugs in Water: Absolute Kinetics and Efficiencies of Hydroxyl Radical and Hydrated Electron Reactions, J. Phys. Chem A., 111, 9019-9024 (2007).
K.L. Swancutt*, S.P. Mezyk, and J.J. Kiddle, Free Radical-Induced Redox Chemistry of Platinum-Containing Anti-Cancer Drugs, Rad. Res., 168, 423-427 (2007).
W. Song, W.J. Cooper, S.P. Mezyk, J. Greaves, and B.M. Peake, Free Radical Destruction of b-Blockers in Aqueous Solution, Env. Sci. Technol., 42, 1256-1261, (2008).
W.J. Cooper, S.P. Mezyk, J. R. Peller, S.K. Cole, W. Song, B.J. Mincher, Studies in Radiation Chemistry: Application to Ozonation and Other Advanced Oxidation Processes, Ozone Sci. Engineer. 30, 58-64 (2008).
S.P. Mezyk, N.A. Landsman*, K.L. Swancutt*, C.N. Bradford*, C.R. Cox*, J.J. Kiddle, T.J. Clore, Free Radical Chemistry of Advanced Oxidation Process Removal of Nitrosamines in Water American Chemical Society Symposium Series 995 (Disinfection By-Products in Drinking Water: Occurrence, Formation, Health Effects, and Control) Eds. T. Karanfil, S.W. Krasner, P. Westerhoff, Y. Xie, 319-333, (2008).
F. L. Rosario-Ortiz, S.P. Mezyk, D.F.R. Doud*, and S.A. Snyder, Quantitative Correlation of Absolute Hydroxyl Radical Rate Constants with Non-Isolated Effluent Organic Matter Bulk Properties in Water, Env. Sci. Technol., 42, 5924-5930 (2008).
F. L. Rosario-Ortiz, S. P. Mezyk, E. C. Wert, D. F. R. Doud*, M. K. Singh*, M. Xin, S. Baik, and S. A. Snyder, Effect of Ozone Oxidation on the Molecular and Kinetic Properties of Effluent Organic Matter J. Adv. Oxidat. Technol. 11, 529-535 (2008).
W.J. Cooper, W. Song, M. Gonsior, D. Kalnina, B.M. Peake, and S.P. Mezyk, Recent Advances in Structure and Reactivity of Dissolved Organic Matter in Natural Waters, Wat. Sci. Tech.: Water Supply WSTWS, 8.6, 615-623, (2008).
L.R. Martin, S.P. Mezyk and B.J. Mincher, Determination of Arrhenius and Thermodynamic Parameters for the Aqueous Reaction of the Hydroxyl Radical with Lactic Acid, J. Phys. Chem. A, 113, 141-145 (2009).
W. Song, W.J. Cooper, B.M. Peake, S.P. Mezyk, M. Nickelsen, K.E. O’Shea, Free Radical Induced Oxidation and Reductive Degradation of N,N’-diethyl-m-toluamide (DEET): Kinetic Studies and Degradation Pathway, Water Res. , 43, 635-642 (2009).
W.J. Cooper, C. Cramer, N.H. Martin, S.P. Mezyk, K.E. O’Shea, C. von Sonntag, Free Radical Mechanisms for the Destruction of Methyl tert-Butyl Ether (MTBE) via Advanced Oxidation Processes, Chem. Rev., 109, 1302-1345, (2009).