Event Title

Photoproduced Reactive Species in Natural Waters: Influence of Chromophoric Dissolved Organic Matter Properties

Location

CSU Ballroom

Start Date

16-4-2013 10:00 AM

End Date

16-4-2013 12:00 PM

Student's Major

Chemistry and Geology

Student's College

Science, Engineering and Technology

Mentor's Name

John Thoemke

Mentor's Department

Chemistry and Geology

Mentor's College

Science, Engineering and Technology

Description

Chromophoric Dissolved Organic Matter (CDOM) is prevalent in natural waters and is the byproduct of natural decay processes. Prior work shows that CDOM properties depend on the sources, and in many cases, two main types of CDOM exist, which are microbial and terrestrial. The former comes from biological activity of microscopic organisms in the water, while the latter is from decayed terrestrial plant material. When CDOM absorbs sunlight, it has the capability to produce several different species, which are highly reactive. Molecular singlet oxygen and the excited triplet state of CDOM were the reactive species studied in this project. Each of these potentially provides a “pathway” for the decomposition of pollutants, which can lead to byproducts that are potentially more benign or more toxic; depending on the specific reaction mechanisms. Prior evidence suggests a correlation between the CDOM source properties and the relative amounts of the different reactive species produced. Knowledge of the specific reactive species that will be produced in a natural water sample will allow more accurate predictions about the decomposition products of specific pollutants. For this project, correlations between optical characteristics of the CDOM (using UV-Visible absorbance and excitation-emission spectra) and the relative amounts of reactive species that are produced by a CDOM sample were performed. Preliminary results are consistent with previous work and suggest that terrestrially-dominated waterways produce lower yields of these reactive species, compared to waterways dominated by microbial CDOM.

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Apr 16th, 10:00 AM Apr 16th, 12:00 PM

Photoproduced Reactive Species in Natural Waters: Influence of Chromophoric Dissolved Organic Matter Properties

CSU Ballroom

Chromophoric Dissolved Organic Matter (CDOM) is prevalent in natural waters and is the byproduct of natural decay processes. Prior work shows that CDOM properties depend on the sources, and in many cases, two main types of CDOM exist, which are microbial and terrestrial. The former comes from biological activity of microscopic organisms in the water, while the latter is from decayed terrestrial plant material. When CDOM absorbs sunlight, it has the capability to produce several different species, which are highly reactive. Molecular singlet oxygen and the excited triplet state of CDOM were the reactive species studied in this project. Each of these potentially provides a “pathway” for the decomposition of pollutants, which can lead to byproducts that are potentially more benign or more toxic; depending on the specific reaction mechanisms. Prior evidence suggests a correlation between the CDOM source properties and the relative amounts of the different reactive species produced. Knowledge of the specific reactive species that will be produced in a natural water sample will allow more accurate predictions about the decomposition products of specific pollutants. For this project, correlations between optical characteristics of the CDOM (using UV-Visible absorbance and excitation-emission spectra) and the relative amounts of reactive species that are produced by a CDOM sample were performed. Preliminary results are consistent with previous work and suggest that terrestrially-dominated waterways produce lower yields of these reactive species, compared to waterways dominated by microbial CDOM.

Recommended Citation

Malecha, Kurtis. "Photoproduced Reactive Species in Natural Waters: Influence of Chromophoric Dissolved Organic Matter Properties." Undergraduate Research Symposium, Mankato, MN, April 16, 2013.
http://cornerstone.lib.mnsu.edu/urs/2013/poster-session-A/27