Issue 4, 2014

Photometric hydroxyl radical scavenging analysis of standard natural organic matter isolates

Abstract

Hydroxyl radical (˙OH) scavenging reaction rate constants of standard natural organic matter (NOM) isolates (k˙OH,NOM) were measured with a rapid background scavenging method, to expand the dataset of published k˙OH,NOM values. The proposed method relies on ˙OH generation with a simple UV/H2O2 AOP-based system. The associated decay of a ˙OH probe compound is monitored with a field-deployable spectrophotometer and k˙OH,NOM is determined through competition kinetics. The resulting k˙OH,NOM values for the six NOM standard isolates ranged from 1.02 (±0.10) × 108 MC−1 s−1 for Suwannee River Fulvic Acid I Standard to 2.03 (±0.12) × 108 MC−1 s−1 for Pony Lake Fulvic Acid Reference NOM, which is within the range reported with more elaborate and time-consuming k˙OH,NOM methods. A slight correlation between nitrogen content and scavenging rate constant was evident while no significant correlation between k˙OH,NOM and atomic composition, carbon structure, weight-average molecular weight, UV absorbance (SUVA254), or fluorescence index (FI) was observed. Overall, the results demonstrate that k˙OH,NOM can be rapidly assessed in NOM isolate samples. The results suggest that this type of rapid field-deployable spectrophotometric method may minimize the need for expensive and time-consuming background scavenging methods, and for models that predict k˙OH,NOM based on other NOM characteristics.

Graphical abstract: Photometric hydroxyl radical scavenging analysis of standard natural organic matter isolates

Supplementary files

Article information

Article type
Paper
Submitted
05 Dec 2013
Accepted
21 Jan 2014
First published
21 Jan 2014

Environ. Sci.: Processes Impacts, 2014,16, 764-769

Author version available

Photometric hydroxyl radical scavenging analysis of standard natural organic matter isolates

J. E. Donham, E. J. Rosenfeldt and K. R. Wigginton, Environ. Sci.: Processes Impacts, 2014, 16, 764 DOI: 10.1039/C3EM00663H

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