Photodegradation of Fluorotelomer Carboxylic 5:3 Acid and Perfluorooctanoic Acid Using Zinc Oxide

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

Environ Pollut. 2018 Dec;243(Pt A):637-644.

PMID: 30219589

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 (365 nm), 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 135 h 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.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP197223362	2,3,5,6-Tetramethylphenylboronic acid		197223-36-2	Price
AP871125712	4-Propoxy-2,3,5,6-tetrafluorophenylboronic acid		871125-71-2	Price

Catalog Number

Product Name

Structure

CAS Number

Price

AP197223362

2,3,5,6-Tetramethylphenylboronic acid

197223-36-2

Price

AP871125712

4-Propoxy-2,3,5,6-tetrafluorophenylboronic acid

871125-71-2

Price

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