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.
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.
https://cornerstone.lib.mnsu.edu/urs/2013/poster-session-A/27
