2024 AIChE Annual Meeting

(231f) Understanding the Fate and Transport of Perfluorooctanesulfonic Acid (PFOS) and Microplastics in Aquatic Environment

Authors

Barbosa, G., University of Alabama
Turner, C., University of Alabama
Esfahani, M., University of Alabama
Microplastics have emerged as a growing environmental concern, attracting considerable attention due to the complexity of their removal and their capacity to transport accompanying pollutants. Owing to their mobility, small size, and propensity to accumulate, microplastics pose toxicity risks to both terrestrial and aquatic organisms, as well as to humans, triggering inflammation and oxidative stress. Additionally, the presence of per- and polyfluoroalkyl substances (PFAS) in water can cause health effects on humans and animals over time. In this work, we delved into the intriguing interplay between these two emerging water contaminants at different conditions (temperature, contact time and pH). Our primary focus centered on unraveling the interaction dynamics between perfluorooctanesulphonic acid (PFOS) and prevalent microplastics, predominantly comprising polyethylene (PE) (20 µm), polypropylene (PP) (17 µm), and polyvinyl chloride (PVC) particles found in water. Our findings revealed PFOS adsorption onto PE, PP, and PVC, reaching peaks of approximately 9%, 12%, and 6% after 24 hours of contact and escalating to 14%, 20%, and 20% within 8 days, respectively. Following this, a noticeable trend of desorption was observed over the subsequent month for each type of microplastic, prompting further investigation through the characterization of PFOS-adsorbed microplastics. Moreover, as temperatures increased from 250 C to 450 C, a notable increase in PFOS adsorption occurred (approximately 41%, 52%, and 48% within 8 days in PE, PP, and PVC, respectively), indicative of an endothermic reaction during the adsorption process. Concurrently, molecular dynamics simulations were employed to model the adsorption mechanism of three different perfluorooctyl PFAS including 30 molecules on PE, PP, and PVC microplastic particles. The molecular simulation results suggest a pronounced dispersive interaction between the polymer and PFAS molecules for PE and PP; while the dispersive interaction dominates the PVC systems, as compared to PE and PP, a much stronger coulombic PFAS-PVC interaction is found.