Size Exclusion Chromatography Reveals Patterns in Preferential Adsorption and Competitive Displacement of Dissolved Organic Matter as a Function of Molecular Size
Primary Faculty Mentor’s Name
David Kreller
Proposal Track
Student
Session Format
Poster
Abstract
Interactions between dissolved organic matter (DOM) and adsorbent surfaces are of substantial interest in environmental science. These interactions have implications for element cycling, soil evolution, carbon sequestration, wastewater treatment and contaminant transport. In this work, the hydrophobic organic acid fraction (HPOA; consisting of humic and fulvic acids) of DOM from the Suwanee River (GA, US, denoted ‘SR’) was interacted with surfaces of naturally occurring metal [Fe, Al] oxide coated quartz sand (retrieved at Oyster, VA (US), herein called ‘Oyster Sand’, OS). This is a new DOM reference material which will be distributed to research groups worldwide in the coming years. A size exclusion chromatography (SEC) method was utilized to provide data to supplement data available in liquid chromatographic (LC) studies of SR-HPOA adsorption and desorption on OS. SEC works by separating molecules by size, high molecular weight constituents elute from the column first. Alsom the SEC data an enrichment and depletion curve is be generated to provide qualitative information. SEC eluent was monitored in UV/Vis absorbance channels 254 and 340 nm. SEC chromatograms indicated that high molecular weight (MW) DOM was being preferentially adsorbed on sand grains. Enrichment and depletion curves were created by subtracting the chromatogram of each fraction from the chromatogram of the final fraction in which no molecules had adsorbed to the OS. The final fraction is an injection which is passed over a fully saturated column, thereby acting an “initial” sample. These curves were successful in showing that high molecular weight molecules were preferentially adsorbed to the OS. They also provide information on the competitive displacement by inorganic ions [hydroxyl (OH-) and phosphate (PO43-). The eluent was subjected to UV-Vis analysis and the data shows a trend of high molecular weight material being released first. The collected data supports that DOM adsorption and desorption on natural metal oxide coated quartz occurs preferentially with high molecular weight molecules.
Keywords
Size exclusion chromatography, SEC, Dissolved organic matter, Adsorption, Desorption
Location
Concourse/Atrium
Presentation Year
2014
Start Date
11-15-2014 2:55 PM
End Date
11-15-2014 4:10 PM
Publication Type and Release Option
Presentation (Open Access)
Recommended Citation
Furio, Anthony R., "Size Exclusion Chromatography Reveals Patterns in Preferential Adsorption and Competitive Displacement of Dissolved Organic Matter as a Function of Molecular Size" (2014). Georgia Undergraduate Research Conference (2014-2015). 104.
https://digitalcommons.georgiasouthern.edu/gurc/2014/2014/104
Size Exclusion Chromatography Reveals Patterns in Preferential Adsorption and Competitive Displacement of Dissolved Organic Matter as a Function of Molecular Size
Concourse/Atrium
Interactions between dissolved organic matter (DOM) and adsorbent surfaces are of substantial interest in environmental science. These interactions have implications for element cycling, soil evolution, carbon sequestration, wastewater treatment and contaminant transport. In this work, the hydrophobic organic acid fraction (HPOA; consisting of humic and fulvic acids) of DOM from the Suwanee River (GA, US, denoted ‘SR’) was interacted with surfaces of naturally occurring metal [Fe, Al] oxide coated quartz sand (retrieved at Oyster, VA (US), herein called ‘Oyster Sand’, OS). This is a new DOM reference material which will be distributed to research groups worldwide in the coming years. A size exclusion chromatography (SEC) method was utilized to provide data to supplement data available in liquid chromatographic (LC) studies of SR-HPOA adsorption and desorption on OS. SEC works by separating molecules by size, high molecular weight constituents elute from the column first. Alsom the SEC data an enrichment and depletion curve is be generated to provide qualitative information. SEC eluent was monitored in UV/Vis absorbance channels 254 and 340 nm. SEC chromatograms indicated that high molecular weight (MW) DOM was being preferentially adsorbed on sand grains. Enrichment and depletion curves were created by subtracting the chromatogram of each fraction from the chromatogram of the final fraction in which no molecules had adsorbed to the OS. The final fraction is an injection which is passed over a fully saturated column, thereby acting an “initial” sample. These curves were successful in showing that high molecular weight molecules were preferentially adsorbed to the OS. They also provide information on the competitive displacement by inorganic ions [hydroxyl (OH-) and phosphate (PO43-). The eluent was subjected to UV-Vis analysis and the data shows a trend of high molecular weight material being released first. The collected data supports that DOM adsorption and desorption on natural metal oxide coated quartz occurs preferentially with high molecular weight molecules.
