- Radiation Chemistry
- Advanced Oxidation/Reduction Processes for Water Treatment
- Free-Radical Kinetics and Mechanisms
- +۴ مورد دیگر
Stephen Mezyk is a Professor of Chemistry at California State University, Long Beach (2009–present) and holds concurrent appointments at Idaho National Laboratory (2025–), Notre Dame Radiation Laboratory (1986–) and Brookhaven National Laboratory (2002–). His research exploits pulse and steady-state radiolysis to quantify free-radical kinetics governing (i) destruction of pharmaceuticals, PFAS and nano-plastics in advanced water-treatment schemes, (ii) radiation stability of actinide/lanthanide separation ligands for closed nuclear fuel cycles, and (iii) redox mechanisms in chemical carcinogenesis. Education Ph.D. in Chemistry, University of Melbourne, Australia, 1989 Research Interests Mezyk’s group operates at the interface of physical chemistry and environmental/nuclear engineering. Using transient absorption and competitive kinetic techniques they map absolute rate constants for reactions of hydrated electrons, hydroxyl and sulfate radicals with trace organics, actinide complexes and polymeric debris. This fundamental database underpins mechanistic models for UV- and radiation-driven advanced oxidation/reduction processes (AOPs/ARPs) aimed at direct potable reuse of wastewater and for safeguarding solvent-extraction flowsheets in advanced nuclear fuel reprocessing. Recent work has expanded to photochemical fragmentation of polyethylene micro- and nanoplastics in natural and engineered aqueous systems, revealing rapid conversion of visible fragments into colloidal “incognito” species detectable only by Raman and LC-MS techniques. Publication Trends Over the past five years Mezyk has averaged >10 peer-reviewed papers annually, 70% appearing in high-impact journals (Environmental Science & Technology, ACS Environmental Au, Dalton Transactions, Physical Chemistry Chemical Physics). The 2024-25 output is dominated by studies coupling temperature-dependent kinetics with computational modelling to predict long-term behaviour of both emerging water contaminants and nuclear-separation ligands under gamma or alpha irradiation. Scientific Awards & Recognition No specific awards are listed in the supplied material; inclusion in multiple DOE-funded Energy Frontier Research Centers and continuous federal funding (NSF, DOE) attest to peer recognition. Advising & Grants Mezyk has mentored >25 graduate students and post-docs, many now co-authors on recent papers (indicated by asterisks). Current and recent funding embraces NSF-CBET for “CAS-MNP: Radical-induced Weathering of Micro- and Nanoplastics”, DOE-NE for “Radiation Chemistry of Trivalent Actinide Separations”, and OCWD/Water Research Foundation projects on methyl nitrate formation during UV-AOP treatment for potable reuse. Laboratories & Teams On campus he directs the Radiation & Free-Radical Kinetics Laboratory (HSCI-358) equipped with 10 MeV electron LINAC and 60-Co gamma source for pulse and steady-state radiolysis. Collaborative access to Notre Dame’s 7-MeV Tandetron and Brookhaven’s LEAF facility expands transient kinetic coverage from ns to ms timescales. A growing cohort of INL colleagues supports work on spent-fuel dissolution chemistry under the DOE-NE SEPST program.
