Aqueous ozonation of furans: Kinetics and transformation mechanisms leading to the formation of α,β-unsaturated dicarbonyl compounds

Garyfalia A Zoumpouli; Zhuoyue Zhang; Jannis Wenk; Carsten Prasse

doi:10.1016/j.watres.2021.117487

Aqueous ozonation of furans: Kinetics and transformation mechanisms leading to the formation of α,β-unsaturated dicarbonyl compounds

Water Res. 2021 Sep 15:203:117487. doi: 10.1016/j.watres.2021.117487. Epub 2021 Jul 31.

Authors

Garyfalia A Zoumpouli¹, Zhuoyue Zhang², Jannis Wenk³, Carsten Prasse⁴

Affiliations

¹ Centre for Doctoral Training, Centre for Sustainable Chemical Technologies, University of Bath, Bath BA2 7AY, UK; Department of Chemical Engineering, University of Bath, Bath BA2 7AY, UK; Water Innovation and Research Centre (WIRC), University of Bath, Bath BA2 7AY, UK; Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
² Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
³ Department of Chemical Engineering, University of Bath, Bath BA2 7AY, UK; Water Innovation and Research Centre (WIRC), University of Bath, Bath BA2 7AY, UK.
⁴ Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address: cprasse1@jhu.edu.

PMID: 34384950
DOI: 10.1016/j.watres.2021.117487

Abstract

Despite the widespread occurrence of furan moieties in synthetic and natural compounds, their fate in aqueous ozonation has not been investigated in detail. Reaction rate constants of seven commonly used furans with ozone were measured and ranged from k_O3 = 8.5 × 10⁴ to 3.2 × 10⁶ M^-1 s^-1, depending on the type and position of furan ring substituents. Transformation product analysis of the reaction of furans with ozone focusing on the formation of toxic organic electrophiles using a novel amino acid reactivity assay revealed the formation of α,β-unsaturated dicarbonyl compounds, 2-butene-1,4-dial (BDA) and its substituted analogues (BDA-Rs). Their formation can be attributed to ozone attack at the reactive α-C position leading to furan ring opening. The molar yields of α,β-unsaturated dicarbonyl compounds varied with the applied ozone concentration reaching maximum values of 7% for 2-furoic acid. The identified α,β-unsaturated dicarbonyls are well-known toxicophores that are also formed by enzymatic oxidation of furans in the human body. In addition to providing data on kinetics, transformation product analysis and proposed reaction mechanisms for the ozonation of furans, this study raises concern about the presence of α,β-unsaturated dicarbonyl compounds in water treatment and the resulting effects on human and environmental health.

Keywords: dicarbonyls; organic micropollutants; reactivity-directed analysis; toxic by-products; transformation products.

MeSH terms

Furans
Humans
Kinetics
Ozone*
Water Pollutants, Chemical* / analysis
Water Purification*

Substances

Furans
Water Pollutants, Chemical
Ozone