CEE Seminar – Environmental Photophysics and Photochemistry of Dissolved Organic Matter

Environmental Photophysics and Photochemistry of Dissolved Organic Matter – Presented by Dr. Garrett McKay

Abstract

Dissolved organic matter (DOM) is a heterogeneous mixture of molecules, whose quality and quantity influences many processes in environmental engineering and science.  For example, in drinking water treatment, DOM is considered a pollutant and substantial efforts are made to remove it prior to disinfection.  In natural aquatic systems, DOM plays a key role in the transport (sorption) and transformation (photochemistry) of natural and anthropogenic chemicals.  Achieving a complete mechanistic understanding of the role of DOM in these processes is made challenging by the complex nature of DOM, with any given sample containing thousands of individual compounds.  This presentation will describe results from to understand the structural complexity of DOM by focusing on its optical and photochemical properties.  Results from fluorescence quenching techniques and borohydride reduction suggests suggests that DOM from different sources contains overlapping pools of chromophores and fluorophores that can broadly be separated into local excited states (LE) and charge-transfer (CT).  The nature and relevance of these different pools of chromophores will be discussed.

 

Bio

Dr. Garrett McKay joined the Zachry Department of Civil & Environmental Engineering at Texas A&M University in September 2019 as an assistant professor.  His research focuses on the fundamental chemistry occurring in natural and engineered systems, including aquatic photochemistry, dissolved organic matter characterization, and treatment of emerging contaminants.  Before joining the faculty at TAMU, he was a postdoctoral scholar at The Colorado School of Mines.  Garrett graduated with his PhD in Environmental Engineering in 2017 from CU Boulder. He is looking forward to contributing to the growing Environmental Engineering program by sharing his passion for chemistry with undergraduate and graduate students through his teaching and research.

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