2012/09/17 by Christopher J. Miller, Siu Man Vincent Lee, Andrew L. Rose +1 · 41 citations
Chemistry · Earth and Planetary Sciences · Environmental Science · #Advanced oxidation water treatment #Aqueous solution #Chemistry #Dissolved organic carbon #Divalent #Environmental chemistry #Fulvic acid #Geochemistry and Elemental Analysis #Geology #Humic acid #Inorganic chemistry #Ion #Ionic bonding #Ionic strength #Kinetics #Marine and coastal ecosystems #Natural organic matter #Oceanography #Organic matter #Physical chemistry #Redox #Salinity #Seawater
paper · doi:10.1021/es3022792
published in Environmental Science & Technology 46(20), 11078-11085 (American Chemical Society)
openalex publication_date 2012/09/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/27
Whereas the oxidation of inorganic Fe(II) by H(2)O(2) in seawater has been well studied, the oxidation of Fe(II) complexes with natural organic matter (NOM) by this ubiquitous oxidant has received little attention. Suwannee River fulvic acid (SRFA), a proxy for terrestrial NOM, is shown to have a much smaller impact upon Fe(II) oxidation kinetics in seawater than the strong effect previously observed in freshwater conditions. However, the oxidation kinetics of Fe(II) in seawater and freshwater can be quantitatively described employing the same mechanistic kinetic model, except that the apparent formation constant of Fe(II)-SRFA complexes is substantially decreased under conditions representative of estuarine and river-influenced coastal waters. This implies that the same basic processes occur in both systems, with differences between Fe(II) oxidation kinetics in seawater and freshwater largely attributable to effects of ionic strength and matrix composition. This was confirmed with studies employing NaCl solutions with or without Mg(2+)/Ca(2+) addition demonstrating that both ionic strength and divalent cations effect a decrease in the Fe(II)-binding affinity of SRFA. The impact of NOM upon iron redox transformation kinetics is therefore greatly influenced by changes in both ionic strength and the presence of cations able to compete with Fe(II) for binding sites.