Presented on April 28, 2022, by Suzanne Witt - Fraunhofer USA - at the 2022 Emerging Contaminants in the Environment Conference (ECEC22)

Perfluoroalkyl acids (PFAAs) are toxic chemicals used in a wide variety of consumer goods and industrial processes. Their highly recalcitrant nature has led to their accumulation in the environment after disposal, resulting in contamination of many different water sources. Ion exchange (IX) is a highly effective technology for removing PFAAs from contaminated water. However, IX does not destroy PFAAs and instead generates a concentrated waste stream. Electrochemical oxidation (EO) is an effective technology for destroying PFAAs, and is a good candidate to be paired with a removal technology such as IX. In this work, EO with boron-doped diamond electrodes was assessed for the destruction of PFAAs in IX still bottoms solutions at the laboratory and semi-pilot scales. For both scales, less than 90 % removal of total PFAAs was achieved with electrochemical treatment of the still bottoms, however the semi-pilot scale exhibited 0.8-fold slower pseudo-first order degradation kinetics compared to the laboratory scale. The differences in performances between the two scales will be discussed to highlight the challenges of scaling up the EO technology. Overall, the results show that EO paired with IX is a promising treatment train approach for permanent, energy efficient PFAA destruction in larger volumes of wastewater.

Download slides: http://hdl.handle.net/2142/114141