TY - JOUR

T1 - Sorption of iodine in soils

T2 - insight from selective sequential extractions and X-ray absorption spectroscopy

AU - Köhler, Fabian

AU - Riebe, Beate

AU - Scheinost, Andreas C.

AU - König, Claudia

AU - Hölzer, Alex

AU - Walther, Clemens

N1 - We thank the Siebold-Sasse Foundation for funding our research.

PY - 2019/8/1

Y1 - 2019/8/1

N2 - The environmental fate of iodine is of general geochemical interest as well as of substantial concern in the context of nuclear waste repositories and reprocessing plants. Soils, and in particular soil organic matter (SOM), are known to play a major role in retaining and storing iodine. Therefore, we investigated iodide and iodate sorption by four different reference soils for contact times up to 30 days. Selective sequential extractions and X-ray absorption spectroscopy (XAS) were used to characterize binding behavior to different soil components, and the oxidation state and local structure of iodine. For iodide, sorption was fast with 73 to 96% being sorbed within the first 24 h, whereas iodate sorption increased from 11–41% to 62–85% after 30 days. The organic fraction contained most of the adsorbed iodide and iodate. XAS revealed a rapid change of iodide into organically bound iodine when exposed to soil, while iodate did not change its speciation. Migration behavior of both iodine species has to be considered as iodide appears to be the less mobile species due to fast binding to SOM, but with the potential risk of mobilization when oxidized to iodate.

AB - The environmental fate of iodine is of general geochemical interest as well as of substantial concern in the context of nuclear waste repositories and reprocessing plants. Soils, and in particular soil organic matter (SOM), are known to play a major role in retaining and storing iodine. Therefore, we investigated iodide and iodate sorption by four different reference soils for contact times up to 30 days. Selective sequential extractions and X-ray absorption spectroscopy (XAS) were used to characterize binding behavior to different soil components, and the oxidation state and local structure of iodine. For iodide, sorption was fast with 73 to 96% being sorbed within the first 24 h, whereas iodate sorption increased from 11–41% to 62–85% after 30 days. The organic fraction contained most of the adsorbed iodide and iodate. XAS revealed a rapid change of iodide into organically bound iodine when exposed to soil, while iodate did not change its speciation. Migration behavior of both iodine species has to be considered as iodide appears to be the less mobile species due to fast binding to SOM, but with the potential risk of mobilization when oxidized to iodate.

KW - Iodine

KW - Migration

KW - RefeSol

KW - Selective sequential extraction

KW - Speciation

KW - XAS

UR - http://www.scopus.com/inward/record.url?scp=85067827081&partnerID=8YFLogxK

U2 - 10.1007/s11356-019-05623-y

DO - 10.1007/s11356-019-05623-y

M3 - Article

C2 - 31214887

AN - SCOPUS:85067827081

VL - 26

SP - 23850

EP - 23860

JO - Environmental Science and Pollution Research

JF - Environmental Science and Pollution Research

SN - 0944-1344

IS - 23

ER -