Details
| Original language | English |
|---|---|
| Pages (from-to) | 4896-4901 |
| Number of pages | 6 |
| Journal | Environmental Science and Technology |
| Volume | 43 |
| Issue number | 13 |
| Early online date | 29 May 2009 |
| Publication status | Published - 1 Jul 2009 |
Abstract
The influence of uranyl-carbonate and calcium-uranyl-carbonate complexations on the kinetics of U(VI) (∼3.4 × 10-3 mol L-1) sorption from NaNO3 and Ca(NO3) 2 solutions on Na- and Ca-bentonites at circumneutral ambient conditions was investigated. Complexation of U(VI) in Ca2UO 2(CO3)3(aq) aqueous species, dominating the U(VI) speciation in Ca(NO3)2 solution, reduces its adsorption on bentonite by a factor of 2-3 in comparison with that in (UO 2)2CO3(OH)3- species, dominating in NaNO3 solution, within the studied period of time (21 days). As a result of the dissolution of accessory calcite, Ca 2UO2(CO3)3(aq) can be formed in the initially Ca-free solution in contact with either Na- or Ca-bentonite. U(VI) adsorption on Na-bentonite is a factor of ∼2 higher than that on Ca-bentonite for solutions with the Ca2UO2(CO 3)3(aq) complex dominating aqueous U(VI) speciation. This favors use of Na-bentonite over that of Ca-bentonite in final disposal of radioactive waste. Furthermore, the observed strong correlation between U(VI) adsorption and Mg release as a result of montmorillonite dissolution indicates in agreement with previous findings that under the applied conditions U(VI)is adsorbed on the edge surface of montmorillonite, which is a major mineral phase of the studied clays.
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Environmental Science(all)
- Environmental Chemistry
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In: Environmental Science and Technology, Vol. 43, No. 13, 01.07.2009, p. 4896-4901.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Influence of (calcium-)uranyl-carbonate complexation on U(VI) sorption on Ca- and Na-bentonites
AU - Meleshyn, A.
AU - Azeroual, M.
AU - Reeck, T.
AU - Houben, G.
AU - Riebe, B.
AU - Bunnenberg, C.
PY - 2009/7/1
Y1 - 2009/7/1
N2 - The influence of uranyl-carbonate and calcium-uranyl-carbonate complexations on the kinetics of U(VI) (∼3.4 × 10-3 mol L-1) sorption from NaNO3 and Ca(NO3) 2 solutions on Na- and Ca-bentonites at circumneutral ambient conditions was investigated. Complexation of U(VI) in Ca2UO 2(CO3)3(aq) aqueous species, dominating the U(VI) speciation in Ca(NO3)2 solution, reduces its adsorption on bentonite by a factor of 2-3 in comparison with that in (UO 2)2CO3(OH)3- species, dominating in NaNO3 solution, within the studied period of time (21 days). As a result of the dissolution of accessory calcite, Ca 2UO2(CO3)3(aq) can be formed in the initially Ca-free solution in contact with either Na- or Ca-bentonite. U(VI) adsorption on Na-bentonite is a factor of ∼2 higher than that on Ca-bentonite for solutions with the Ca2UO2(CO 3)3(aq) complex dominating aqueous U(VI) speciation. This favors use of Na-bentonite over that of Ca-bentonite in final disposal of radioactive waste. Furthermore, the observed strong correlation between U(VI) adsorption and Mg release as a result of montmorillonite dissolution indicates in agreement with previous findings that under the applied conditions U(VI)is adsorbed on the edge surface of montmorillonite, which is a major mineral phase of the studied clays.
AB - The influence of uranyl-carbonate and calcium-uranyl-carbonate complexations on the kinetics of U(VI) (∼3.4 × 10-3 mol L-1) sorption from NaNO3 and Ca(NO3) 2 solutions on Na- and Ca-bentonites at circumneutral ambient conditions was investigated. Complexation of U(VI) in Ca2UO 2(CO3)3(aq) aqueous species, dominating the U(VI) speciation in Ca(NO3)2 solution, reduces its adsorption on bentonite by a factor of 2-3 in comparison with that in (UO 2)2CO3(OH)3- species, dominating in NaNO3 solution, within the studied period of time (21 days). As a result of the dissolution of accessory calcite, Ca 2UO2(CO3)3(aq) can be formed in the initially Ca-free solution in contact with either Na- or Ca-bentonite. U(VI) adsorption on Na-bentonite is a factor of ∼2 higher than that on Ca-bentonite for solutions with the Ca2UO2(CO 3)3(aq) complex dominating aqueous U(VI) speciation. This favors use of Na-bentonite over that of Ca-bentonite in final disposal of radioactive waste. Furthermore, the observed strong correlation between U(VI) adsorption and Mg release as a result of montmorillonite dissolution indicates in agreement with previous findings that under the applied conditions U(VI)is adsorbed on the edge surface of montmorillonite, which is a major mineral phase of the studied clays.
UR - http://www.scopus.com/inward/record.url?scp=67649921822&partnerID=8YFLogxK
U2 - 10.1021/es900123s
DO - 10.1021/es900123s
M3 - Article
C2 - 19673282
AN - SCOPUS:67649921822
VL - 43
SP - 4896
EP - 4901
JO - Environmental Science and Technology
JF - Environmental Science and Technology
SN - 0013-936X
IS - 13
ER -