Iodination of humic acid samples from different origins

Reiller, Pascal E.; Mercier‐Bion, Florence; Gimenez, Nicolas; Barré, Nicole; Miserque, F.

doi:10.1524/ract.2006.94.9-11.739

Cited by 69 publications

(25 citation statements)

References 26 publications

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“…From a study of reaction kinetics, Warner et al (2000) concluded that iodination of natural organic matter followed the same mechanism as iodination of phenols, through reaction with molecular iodine, I 2 . The same electrophilic substitution mechanism was suggested by Reiller et al (2006) in their study of iodination of humic acids. von Gunten (1999, 2000) also demonstrated that iodide can be oxidised to HOI and thereby react with organic compounds (e.g.…”

Section: Introductionsupporting

confidence: 70%

“…Below pH 6 iodate sorption is predominantly to iron and aluminium oxides, with iron oxides becoming increasingly important as pH drops (Whitehead, 1974b). Iodate is non-reactive toward organic matter and studies have shown that it is reduced to electrophilic species such HOI or I 2 before incorporation into the organic structure of humus (Francois, 1987a,b;von Gunten, 1999, 2000;Radlinger and Heumann, 2000;Warner et al, 2000;Reiller et al, 2006;Schlegel et al, 2006;Steinberg et al, 2008c). The reduction of iodate has been shown to be faster under acidic conditions (Brummer and Field, 1979); in soils, humic substances can reduce iodate due to their electrondonor characteristics (Wilson and Weber, 1979).…”

Section: Iodatementioning

confidence: 99%

“…In order to interact with soil organic matter it has been shown that iodide must be oxidised to an intermediate such as I 2 or HOI (Warner et al, 2000;Reiller et al, 2006;Schlegel et al, 2006). Metal (Fe, Mn, Al) oxide phases and soil organic matter are both possible oxidising agents.…”

Section: Iodidementioning

confidence: 99%

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Iodine dynamics in soils

Shetaya

Young

Watts

et al. 2012

Geochimica et Cosmochimica Acta

134

118

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We investigated changes in iodine ( 129 I) solubility and speciation in nine soils with contrasting properties (pH, Fe/Mn oxides, organic carbon and iodine contents), incubated for nine months at 10 and 20°C. The rate of 129 I sorption was greater in soils with large organic carbon contents (%SOC), low pH and at higher temperatures. Loss of iodide (I À ) from solution was extremely rapid, apparently reaching completion over minutes-hours; iodate (IO À 3 ) loss from solution was slower, typically occurring over hours-days. In all soils an apparently instantaneous sorption reaction was followed by a slower sorption process for IO À 3 . For iodide a faster overall reaction meant that discrimination between the two processes was less clear. Instantaneous sorption of IO À 3 was greater in soils with high Fe/Mn oxide content, low pH and low SOC content, whereas the rate of time-dependent sorption was greatest in soils with higher SOC contents. Phosphate extraction (0.15 M KH 2 PO 4 ) of soils, $100 h after 129 I spike addition, indicated that concentrations of sorbed inorganic iodine ( 129 I) were very low in all soils suggesting that inorganic iodine adsorption onto oxide phases has little impact on the rate of iodine assimilation into humus. Transformation of dissolved inorganic 129 IO À 3 and 129 I À to sorbed organic forms was modelled using a range of reactionand diffusion-based approaches. Irreversible and reversible first order kinetic models, and a spherical diffusion model, adequately described the kinetics of both IO À 3 and I À loss from the soil solution but required inclusion of a distribution coefficient (k d ) to allow for instantaneous adsorption. A spherical diffusion model was also collectively parameterised for all the soils studied by using pH, soil organic carbon concentration and combined Fe + Mn oxide content as determinants of the model parameters (k d and D/r 2 ). The kinetic model parameters were not directly related to a single soil parameter; inclusion of pH, SOC, oxide content and temperature was necessary to describe the observed behaviour. From the temperature-dependence of the sorption data the activation energy (E a ) for 129 IO À 3 transformation to organic forms was estimated to be $43 kJ mol À1 . The E a value was independent of %SOC and was consistent with a reaction mechanism slower than pore diffusion or physical adsorption, but faster than most surface reactions.

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Section: Introductionsupporting

confidence: 70%

Section: Iodatementioning

confidence: 99%

See 1 more Smart Citation

Iodine dynamics in soils

Shetaya

Young

Watts

et al. 2012

Geochimica et Cosmochimica Acta

134

118

View full text Add to dashboard Cite

show abstract

“…Hou et al (2003) studied the fate of radioactive 129 I deposited on soils from the Chernobyl area and sediments from the Irish Sea, following the Chernobyl nuclear reactor accident. Many other workers have also reported the importance of organic matter in binding iodine (Whitehead, 1973;Bors et al, 1988;Yamada et al, 2002;Bostock et al, 2003), believed to be primarily due to the formation of covalent bonds between iodine and humic macromolecules (Mercier et al, 2000;Reiller et al, 2006). The data of Hou et al (2003) are summarized in Figure 11.2.…”

Section: Sorption Of Iodine Onto Soil Solidsmentioning

confidence: 98%

Transfers of Iodine in the Soil–Plant–Air System

Ashworth

2009

Comprehensive Handbook of Iodine

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“…In the IR spectra of III and V, stretching vibrations of the carbonyl groups appeared at 1737, 1794 (III) and 1737 cm -1 (V). Salts III and V displayed in the UV spectra absorption bands typical of iodide (λ 226 nm) and triiodide anions (λ 287, 362 nm)[7].…”

mentioning

confidence: 99%