Date of Award
2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Civil and Environmental Engineering
First Advisor
Appala Raju Badireddy
Abstract
Per- and polyfluoroalkyl substances (PFAS) have become integral to modern life due to their unique chemical and physical properties. However, growing concerns persist regarding their toxicity and environmental persistence. Current detection methods - primarily chromatographic techniques coupled with mass spectrometry- are accurate but costly, time-intensive, and confined to laboratory settings. To more effectively evaluate human exposure risks, there is a pressing need for a simpler, faster, and more affordable detection approach that is well-suited for field deployment.This study presents a novel optical sensing approach employing nitrogen-doped carbon quantum dots (N-CDs) for detection of PFAS in drinking water. Existing PFAS sensors often face challenges related to limited selectivity, sensitivity, and portability. In response, this research aims to establish a foundation for the deployment of practical, field-deployable sensors. As an initial step, we explored the interaction mechanisms between N-CDs and five PFAS compounds regulated by the U.S. Environmental protection Agency (EPA): perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexanoic acid (PFHxA), perfluorononanoic acid (PFNA), and nonafluorobutane-1-sulfonic acid (PFBS), selected for their diverse carbon chain lengths and functional groups. To elucidate these interactions, we conducted a comprehensive suite of physicochemical characterizations, including hydrodynamic size, zeta potential, UV-vis absorbance, and fluorescence properties. Bond formation and surface chemistry changes were further confirmed using X-ray photoelectron spectroscopy (XPS). These analysis enabled us to monitor binding interactions and aggregation behavior, offering crucial insights into the sensitivity and selectivity of N-CDs toward the target PFAS compounds. Our findings indicate that PFAS compounds with similar functional groups exhibit comparable interaction profiles, with electrostatic interactions emerging as the dominant mechanism. Selectivity assessment revealed that the primary interferences stem from structurally similar PFAS, underscoring the potential of this N-CDs based sensing platform to differentiate among various PFAS types. Overall, this work provides a fundamental understanding of the physicochemical interactions between N-CDs and PFAS, paving the way for the development of highly selective and sensitive optical sensors for real-time monitoring of drinking water quality.
Language
en
Number of Pages
87 p.
Recommended Citation
Chonnambi, Abhina, "Mechanistic Insights Into Nitrogen-Doped Carbon Quantum Dot- Per-And Polyfluoroalkyl Substances (pfas) Interactions In Drinking Water For Advanced Optical Sensing" (2025). Graduate College Dissertations and Theses. 2155.
https://scholarworks.uvm.edu/graddis/2155