Photodegradation of fluorotelomer carboxylic 5:3 acid and perfluorooctanoic acid using zinc oxide. Academic Article uri icon

abstract

  • Occurrence of per- and poly-fluoroalkyl substances (PFASs) in the environment and biota has raised a great concern to public health because these compounds are persistent, bioaccumulative, and toxic. Biodegradation of polyfluoroalkyl substances, particularly long-chain fluorotelomer-based products, can lead to production of various short-chain PFASs, with 5:3 fluorotelomer carboxylic acid (referred as 5:3 FTCA hereafter) as a dominant polyfluoroalkyl metabolite. Perfluoroalkyl acids, particularly perfluorooctanoic acid (PFOA), are toxic and current removal methods are not cost-effective. This study reports the photodegradation of 5:3 FTCA and PFOA using ZnO as a photocatalyst under neutral pH and room temperature conditions. Under long UV wavelength (365nm), both tetrapod and commercial ZnO can photodegrade 5:3 FTCA. Five removal products-perfluorohexanoic acid, perfluoropentanoic acid, perfluorobutyric acid, 5:2 fluorotelomer carboxylic acid (5:2 FTCA), and inorganic fluoride-were identified, with PFBA and F- as dominant end products. SEM and XPS high-resolution scans on the surface of the utilized ZnO showed less units of CF2 than that in 5:3 FTCA, supporting occurrence of photodegradation of 5:3 FTCA by ZnO. Defluorination of PFOA was not observed with ZnO only, but at pH 5 and in the co-presence of Fe-citrate. PFOA defluorination increased from 0.93% after 3 days of UV light exposure to 3.9% after additional 135h under direct sunlight exposure. To the authors' best knowledge, this is the first report studying ZnO-catalyzed photodegradation of 5:3 FTCA, and examining the Fe co-addition for PFOA defluorination.

published proceedings

  • Environ Pollut

altmetric score

  • 2.35

author list (cited authors)

  • Abada, B., Alivio, T., Shao, Y., O'Loughlin, T. E., Klemashevich, C., Banerjee, S., Jayaraman, A., & Chu, K.

citation count

  • 12

complete list of authors

  • Abada, Bilal||Alivio, Theodore EG||Shao, Yiru||O'Loughlin, Thomas E||Klemashevich, Cory||Banerjee, Sarbajit||Jayaraman, Arul||Chu, Kung-Hui

publication date

  • December 2018