Characterizing hydroxyl radical formation from the light-driven Fe(II)-peracetic acid reaction, a key process for aerosol-cloud chemistry.
Author(s)
Type
Journal Article
Abstract
The reaction of peracetic acid (PAA) and Fe(II) has recently gained attention due to its utility in wastewater treatment and its role in cloud chemistry. Aerosol-cloud interactions, partly mediated by aqueous hydroxyl radical (OH) chemistry, represent one of the largest uncertainties in the climate system. Ambiguities remain regarding the sources of OH in the cloud droplets. Our research group recently proposed that the dark and light-driven reaction of Fe(II) with peracids may be a key contributor to OH formation, producing a large burst of OH when aerosol particles take up water as they grow to become cloud droplets, in which reactants are consumed within 2 min. In this work, we quantify the OH production from the reaction of Fe(II) and PAA across a range of physical and chemical conditions. We show a strong dependence of OH formation on ultraviolet (UV) wavelength, with maximum OH formation at λ = 304 ± 5 nm, and demonstrate that the OH burst phenomenon is unique to Fe(II) and peracids. Using kinetics modeling and density functional theory calculations, we suggest the reaction proceeds through the formation of an [Fe(II)-(PAA)2(H2O)2] complex, followed by the formation of a Fe(IV) complex, which can also be photoactivated to produce additional OH. Determining the characteristics of OH production from this reaction advances our knowledge of the sources of OH in cloudwater and provides a framework to optimize this reaction for OH output for wastewater treatment purposes.
Date Issued
2024-04-30
Date Acceptance
2024-03-27
Citation
Environmental Science and Technology (Washington), 2024, 58 (17), pp.7505-7515
ISSN
0013-936X
Publisher
American Chemical Society
Start Page
7505
End Page
7515
Journal / Book Title
Environmental Science and Technology (Washington)
Volume
58
Issue
17
Copyright Statement
Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under
CC-BY 4.0.
CC-BY 4.0.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/38619820
Subjects
Aerosols
Hydroxyl Radical
Iron
Kinetics
Light
Peracetic Acid
Fe(IV)
Fenton chemistry
iron photochemistry
kinetics model
peroxy acids
pH dependence
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2024-04-15