2025 AIChE Annual Meeting

(515b) Unconventional Reaction and Separation Systems for Perfluorooctanoic Acid (PFOA) Remediation

Authors

Paola Perez-Vega - Presenter, West Virginia University
Grace Neller, West Virginia University
Nicole Robinette, West Virginia University
Jianli Hu, West Virginia University
Oishi Sanyal, West Virginia University
The goal of this work is to develop a unique membrane-facilitated microwave irradiation process for the one-step degradation and separation of perfluorooctanoic acid (PFOA). Perfluoro alkyl substances (PFAS) have been widely reported as being toxic to human health; with the most recent EPA regulations setting it at 0.004 ppt for PFOA. Depending on the source, PFOA levels in the feed stream could be very low (ppb/ppt); therefore, to ensure the sensitivity necessary for this work, pre-concentrating the feed prior to a degradation process is required.

Our approach involves designing a zeolite-layered polymer membrane which will facilitate rapid concentration of PFOA at the membrane surface to enable the microwave-irradiated breakdown, via hot-spot heating. The properties of the underlying membrane will be tailored to reject the degraded by-products of the reaction. This design avoids the need for multi-stage degradation and separation processes and enables continuous operation which in turn, could allow its integration in a wastewater treatment plant without significant infrastructure changes. In our previous research, we have evaluated a few commercial membranes, ranging from ultrafiltration to reverse osmosis types, to determine their optimum separation performance. In addition, our preliminary results using zeolites for PFOA adsorption have revealed >90% adsorption of PFOA and regeneration methods involving sequential methanol and water washes have also been developed . Microwave irradiation is considered a more energy efficient process compared to thermal processes that typically need temperatures ranging from 700oC -900oC. However, identification of the degradation byproducts could be challenging therefore, my current work is focused on analyzing traditional thermal degradation process for the identification and quantification of PFOA byproducts. Using liquid chromatography and mass spectroscopy (LC-MS/MS), we aim to quantify the percent degradation and defluorination with respect to different process parameters (e.g temperature, time). Once the protocols for traditional thermal process are identified, a similar methodology will be adapted for the microwave process. Finally, the zeolite will be incorporated within our polymer membrane and installed into a microwave reactor to facilitate simultaneous separation and degradation of PFOA and its byproducts.