Photochemical production of the hydroxyl radical in Antarctic waters

Qian, Jianguo; Mopper, Kenneth; Kieber, David J.

doi:10.1016/s0967-0637(00)00068-6

Cited by 86 publications

(71 citation statements)

References 20 publications

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“…∑ OH pro- 1.0 ± 0.2 ¥ 10 -3 6.5 ¥ 10 -4 120 1.2 ¥ 10 -3 6.8 ¥ 10 -4 410 E. M. White, P. P. Vaughan and R. G. Zepp Photo-Fenton produced ∑OH and CDOM photobleaching duction in Mississippi River Plume water was on the same order of magnitude (10 -11 M s -1 ) as waters from Biscayne Bay and Vineyard Sound as well as various lakes (Haag and Hoigné, 1985;Zepp et al, 1987;Mabury, 1993). The Florida Keys sample had a lower rate of ∑ OH production (10 -12 M s -1 ), similar to samples from Antarctic waters (Qian et al, 2001) as well as the Gulf Stream and the Sargasso Sea ). Experimentally determined rates of ∑ OH production were normalized to the absorption coefficient at 350 nm (a 350 ) in order to directly compare different water samples (Hu et al, 2002).…”

Section: Optical Properties Of Cdommentioning

confidence: 60%

Role of the photo-Fenton reaction in the production of hydroxyl radicals and photobleaching of colored dissolved organic matter in a coastal river of the southeastern United States

White

Vaughan

Zepp

2003

Aquatic Sciences - Research Across Boundaries

150

149

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Photochemical reactions involving colored dissolved organic matter (CDOM) in natural waters are important determinants of nutrient cycling, trace gas production and control of light penetration into the water column. In this study the role of the hydroxyl radical ( ∑ OH) in CDOM photodegradation was explored as well as the contribution of photo-Fenton chemistry to ∑ OH formation. Photochemically produced ∑ OH was observed under aerobic and dioxygen-depleted conditions in highly colored, acidic natural water samples obtained from a freshwater reach of the Satilla River, a river in the southeastern United States. Net aerobic ∑ OH formation along with the production of hydrogen peroxide and Fe(II) provided evidence of photo-Fenton produced ∑ OH. A reduction in ∑ OH production in the presence of iron chelators further suggests the Aquat. Sci. 65 (2003) 402-414 Aquatic Sciences importance of iron and the photo-Fenton reaction in this water. Apparent quantum yield values for the photochemical production of ∑ OH were determined from 300-320 nm. In addition, the relationship between ∑ OH photoproduction and effects of irradiation on the optical properties of CDOM was examined. Changes in the light absorption and fluorescence properties of water samples from the Satilla River and other natural waters were compared to ∑ OH production rates. The ability of constituents of Satilla River water, principally the dissolved organic matter, to scavenge ∑ OH was also considered. Results indicate that the photoFenton reaction accounts for more than 70% of total photochemical ∑ OH production in Satilla River water. Given the significant levels of ∑ OH produced in this water, it is possible that ∑ OH influences CDOM photobleaching.

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Section: Optical Properties Of Cdommentioning

confidence: 60%

Role of the photo-Fenton reaction in the production of hydroxyl radicals and photobleaching of colored dissolved organic matter in a coastal river of the southeastern United States

White

Vaughan

Zepp

2003

Aquatic Sciences - Research Across Boundaries

150

149

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“…pH also influences the photoactivity of Fe species that take part to DOM photomineralization (Vione et al, 2009) (Table 1); (vii) The light intensity (UV-B, UV-A and PAR: photosynthetically active radiation) is a key factor in the photochemical reactions and controls the production of reactive transients that correspondingly enhance the photodegradation processes (Granéli et al, 1998;Bertilsson and Tranvik, 2000;Qian et al, 2001;Garcia et al, 2005;Randall et al, 2005). Interestingly, the decrease of fluorescence upon addition of NO 2 -that is a major •OH source (Mack and Bolton, 1999) was relatively limited (3%).…”

Section: Controlling Factors and Impacts Of Dom Fluorescence Loss Upomentioning

confidence: 99%

Photochemical, microbial and metal complexation behavior of fluorescent dissolved organic matter in the aquatic environments

Mostofa

Liu

et al. 2011

Geochem. J.

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“…In natural waters, many photochemical reactions are driven by OH, which is one of the most reactive oxidants (E = +1.83 V) [21,22,23]. Major sources of OH in natural waters are the nitrate (NO 3 -) and nitrite (NO 2 -) photolysis, initiated by UV-B and UV-A (315-400 nm), respectively, as well as the photolysis of colored dissolved organic matter (CDOM), initiated by both UV-B and UV-A [24,25,26]. Photochemical oxidation reactions may substantially modify molecular distribution and bacterial availability of dissolved organic compounds in natural waters and then play a significant role in aquatic carbon cycle [27,28].…”

Section: Introductionmentioning

confidence: 99%

“…NO 3 -was chosen as photosensitizer and source of OH radicals since (i) quantum yield of OH formation (Φ OH ) from NO 3 -photolysis is well known [25,26,29], (ii) NO 3 -is very poor OH scavenger (k < 1.10 5 s -1 ) compared to NO 2 -(k = 1.10 10 s -1 ) in aqueous solutions [25] and (iii) in natural waters NO 3 -is often found in much higher concentrations than NO 2 -. The production of OH from the UV-B photolysis of NO 3 -is described by the equations [30,31]:…”

Section: Introductionmentioning

confidence: 99%

Hydroxyl radical-induced photochemical formation of dicarboxylic acids from unsaturated fatty acid (oleic acid) in aqueous solution

Tedetti

Kawamura

Narukawa

et al. 2007

Journal of Photochemistry and Photobiology A: Chemistry

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In this study, we assess under laboratory controlled conditions the direct and hydroxyl radical ( OH)-induced photochemical production of low molecular weight (LMW) dicarboxylic acids and related compounds (C 2 -C 9 ) (DCAs) from oleic acid (cis-9-octadecenoic, 9C 18 ) in aqueous solution. Nitrate (NO 3 -)-amended and unamended oleate solutions were irradiated under ultraviolet-B radiation (UV-B, 313 nm) for 5 h, with NO 3 -being the source of OH. The OH-induced photochemical production of DCAs (C 2di -C 9di ) (165 ± 32 nM h -1 ) was much higher than that induced by the direct effect of UV-B (33 ± 31 nM h -1 ), accounting for 85% of the total (direct + OH-induced) photochemical production of DCAs (C 2di -C 9di ) (194 ± 6 nM h -1 ). Azelaic acid (C 9di ) was the dominant photoproduct (comprising 63 and 44% of DCAs in the direct and OH-induced photochemical production, respectively) followed by C 8di , C 7di and C 6di , whereas shorter chain compounds (C 2di -C 5di ) were minor produced species. Using our estimate of OH photoproduction (P-OH in nM h -1 ), the production of C 9di from 50 µM of oleic acid was evaluated to ~ 36 nM (nM OH) -1 . We propose in this work a chemical mechanism for the reaction of OH with oleic acid in aqueous solution from the cleavage of its double bond, and the subsequent formation of DCAs through oxidation and decarboxylation processes.

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Photochemical production of the hydroxyl radical in Antarctic waters

Cited by 86 publications

References 20 publications

Role of the photo-Fenton reaction in the production of hydroxyl radicals and photobleaching of colored dissolved organic matter in a coastal river of the southeastern United States

Role of the photo-Fenton reaction in the production of hydroxyl radicals and photobleaching of colored dissolved organic matter in a coastal river of the southeastern United States

Photochemical, microbial and metal complexation behavior of fluorescent dissolved organic matter in the aquatic environments

Hydroxyl radical-induced photochemical formation of dicarboxylic acids from unsaturated fatty acid (oleic acid) in aqueous solution

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