Abstract
Cesium uptake by plants depends on adsorption/desorption reactions in the soil, as well as root uptake processes controlled by the plant. In this study, sorption and desorption of Cs+ on reference illite (lMt-1) was investigated in the presence of oxatate to gain understanding of mechanisms by which plant root exudates may influence Cs+ bioavailability in micaceous soils. Cesium sorption on illite decreased significantly as oxalate concentration increased from 0.4 to 2 mM. Cesium desorption from illite increased significantly with increasing oxalate concentration. Desorption of Cs+ by exchange with Na+, Ca2+ and Mg2+ was significantly enhanced in the presence of oxalate as selectivity for Cs-decreased with respect to these ions in the presence of oxalate. On the other hand, oxalate had little effect on the Cs+/K+ selectivity coefficient. This suggests that oxalate treatments increase the relative proportion of exchange sites that are not highly selective for Cs+ and K+; e.g. 'planar' sites. The results indicate that oxalate plays an important role in Cs+ binding on illite and, therefore, plant rhizosphere chemistry is likely to alter Cs+ bioavailability in micaceous soils.
Original language | English |
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Pages (from-to) | 375-381 |
Number of pages | 7 |
Journal | Clays and Clay Minerals |
Volume | 52 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1 Jun 2004 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Frayed-edge sites
- Phytoremediation
- Rhizosphere
- Weathering