Presentation Title

Initial steps in the development of an autonomous Dissolved Organic Carbons (DOC) Analyzer

Authors' Names

Alec Johnson

Presentation Type

Poster Presentation

Abstract/Artist Statement

Dissolved Organic Carbons (DOC) are the portion of carbon containing material in waters that have organic carbon incorporated in their structure. It is important to study DOC in aquatic systems for a variety of reasons, including both environmental monitoring as well as waste management. For example, not only can DOC alter aquatic ecosystem chemistry by contributing to acidification of waters, it can also lead to formation of harmful byproducts such as chloroform, or even complex with trace metals in the environment to produce more toxic forms of these metals, including metals such as mercury.

DOC can vary dramatically over time in natural waters and characterizing the patterns and drivers of DOC variability and requires information spanning a wide range of temporal resolution. This is the problem that my current research is trying to address. Although long-term investigations of DOC dynamics are common, studies done at a high temporal resolution are lacking due to the complex logistics and laboratory costs surrounding DOC analysis in remote environments. Currently there are no in-situ instruments that are dedicated to DOC analysis.

Common laboratory methods for quantification of DOC include High Temperature Oxidation/Combustion methods (HTOC), which involves complete oxidation of DOC to CO2 in extreme heat, persulfate oxidation which is a type of chemically-assisted degradation, as well as UV absorption or fluorescence methods. In the HTOC and persulfate methods, the generated CO2 is quantified using infrared absorption. Due to the high energy demand that would require for full degradation of organic matter for an in-situ instrument, my current research has been working with Persulfate oxidation techniques paired with UV-light degradation, an oxidation process which requires less energy, for quantification of DOC.

Using the chemically-catalyzed persulfate method, I have done experiments both trying to achieve complete oxidation for determination of DOC in an energy-efficient method as well as approximating DOC concentrations using oxidation rates, a method which would be even more energy efficient. The project has also been trying to move in the direction of using UV-LEDs as the main source of UV-generated light to be used for degradation. UV-LEDs also have lower energy requirements than traditional sources of UV-light, such as a Mercury-lamp sources. These UV-LEDs have not been on the market for a very long time, and the usefulness of them for DOC quantification has yet to be fully explored.

This presentation will describe current research that I have been working on regarding development of this system and background experimentation, as well as exploring and understanding the data that has come from them. In addition, the presentation will describe possible future directions the project may head in for the full development of a dedicated in-situ DOC-analyzing instrument.

Mentor Name

Michael DeGrandpre

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Feb 22nd, 5:00 PM Feb 22nd, 6:00 PM

Initial steps in the development of an autonomous Dissolved Organic Carbons (DOC) Analyzer

UC North Ballroom

Dissolved Organic Carbons (DOC) are the portion of carbon containing material in waters that have organic carbon incorporated in their structure. It is important to study DOC in aquatic systems for a variety of reasons, including both environmental monitoring as well as waste management. For example, not only can DOC alter aquatic ecosystem chemistry by contributing to acidification of waters, it can also lead to formation of harmful byproducts such as chloroform, or even complex with trace metals in the environment to produce more toxic forms of these metals, including metals such as mercury.

DOC can vary dramatically over time in natural waters and characterizing the patterns and drivers of DOC variability and requires information spanning a wide range of temporal resolution. This is the problem that my current research is trying to address. Although long-term investigations of DOC dynamics are common, studies done at a high temporal resolution are lacking due to the complex logistics and laboratory costs surrounding DOC analysis in remote environments. Currently there are no in-situ instruments that are dedicated to DOC analysis.

Common laboratory methods for quantification of DOC include High Temperature Oxidation/Combustion methods (HTOC), which involves complete oxidation of DOC to CO2 in extreme heat, persulfate oxidation which is a type of chemically-assisted degradation, as well as UV absorption or fluorescence methods. In the HTOC and persulfate methods, the generated CO2 is quantified using infrared absorption. Due to the high energy demand that would require for full degradation of organic matter for an in-situ instrument, my current research has been working with Persulfate oxidation techniques paired with UV-light degradation, an oxidation process which requires less energy, for quantification of DOC.

Using the chemically-catalyzed persulfate method, I have done experiments both trying to achieve complete oxidation for determination of DOC in an energy-efficient method as well as approximating DOC concentrations using oxidation rates, a method which would be even more energy efficient. The project has also been trying to move in the direction of using UV-LEDs as the main source of UV-generated light to be used for degradation. UV-LEDs also have lower energy requirements than traditional sources of UV-light, such as a Mercury-lamp sources. These UV-LEDs have not been on the market for a very long time, and the usefulness of them for DOC quantification has yet to be fully explored.

This presentation will describe current research that I have been working on regarding development of this system and background experimentation, as well as exploring and understanding the data that has come from them. In addition, the presentation will describe possible future directions the project may head in for the full development of a dedicated in-situ DOC-analyzing instrument.