EAGER: Evaluating the Mechanisms of Perfluorinated Chemical Degradation by a Novel Plasma-Based Water Treatment Process

Clarkson University, Potsdam NY

Investigators

Abstract

1630854 Mededovic Perfluoroalkyl compounds, that is those compounds that have fluorine attached to a carbon, have recently received considerable attention due to their ubiquitous presence in the environment. The presence of perfluoroalkyl compounds is problematic due to the lack of effective treatment technologies. The objective of this proposed research to develop an effective treatment, results from technology recently developed in the PIs' laboratories, the foaming electrical discharge plasma reactor that rapidly and efficiently degrades many chemicals including pharmaceuticals, personal care products, disinfection byproducts, and perfluoroalkyl compounds. The research objective of this project is to advance the fundamental understanding of the chemical reaction mechanisms by which reactive species produced by the foaming plasma reactor transform perfluoroalkyl compounds in water, evaluate the performance of the reactor for additional perfluoroalkyl substances, and identify potential degradation byproducts. The major hypothesis to be tested in this project is that free and aqueous electrons are the species responsible for the primary degradation reactions of perfluoroalkyl compounds. Radical propagation and termination reactions involving the formed radicals and electrons may be driven by any other species including hydroxyl radicals, hydrogen radicals, hydroperoxyl radicals and oxygen radical anions. To test these hypotheses, the experimental plan involves spectroscopic, radical scavenging, and state-of-the-art analytical techniques to determine the species responsible for the degradation of these compounds and their byproducts. The development of a versatile, robust and cost-effective technology that can rapidly and efficiently degrade perfluoroalkyl compounds and other contaminants of emerging concern in industrial effluent and groundwater before they can impact rivers and drinking water supply networks would likely be widely adopted and have a significant positive impact on water quality. The project is designed to answer critical questions: 1. Is the plasma-based water treatment equally effective for perfluorinated alkane substances other than perfluorinated octyl acids and perfluorinated octyl sulfonates? 2. What is the fate of these compounds during treatment and what are the key chemical species responsible for their transformation and what are the final products? 3. Can free electrons degrade short- and long-chained perfluorinated alkane substances or other oxidative radical contributing species? 4. Are transformation pathways similar for different perfluorinated alkane substances? Do physicochemical properties of the compounds (e.g., chain length) play a role in their extent of degradation? 5. Does the presence of co-contaminants lower the treatment efficiency? The project will involve both graduate and undergraduate students. Undergraduate students, who will serve as assistants to graduate students, will be recruited through institutional pipeline programs at the Institution.