Monitoring and Modeling Oxygenated PAHs Formed During Graphene Oxide Phototransformation

Poster Presentation

Prepared by D. Bouchard1, Y. Han2, W. Henderson1, R. Zepp1, C. Knightes1
1 - USEPA, 960 College Station Road, Athens, GA, 30605, United States
2 - ORISE, 960 college Station Road, Athens, GA, 30605, United States


Contact Information: bouchard.dermont@epa.gov; 706-355-8333


ABSTRACT

The production and potential applications of graphene family nanomaterials (GFN) may result in unintended releases of these materials into the environment. Like graphene, graphene oxide (GO) exists as 2-dimensional sheets, but GO is much more readily dispersed in water due to the presence of edge carboxyl groups as well as hydroxyl and epoxy groups in the basal plane. After dispersal in a surface water, GO may be transformed under sunlight to yield photoproducts that include oxygenated PAHs. In this work, we identify and quantify the major carboxylated and hydroxylated PAH photoproducts generated during GO transformation under sunlight using LC/MS-MS with neutral loss scanning and multiple reaction monitoring modes. In addition, the chemical properties estimator, SPARC (Sparc Performs Automated Reasoning in Chemistry), is used to estimate oxygenated PAH solubility and speciation in surface waters. SPARC output is then utilized to parameterize the Water Quality Analysis Simulation Program (WASP8) to simulate potential PAH concentrations in surface waters and in sediments.