TY - JOUR
T1 - Adsorption of Eu3+ to smectites and fluoro-tetrasilicic mica
AU - Okada, Tomohiko
AU - Ehara, Yusuke
AU - Ogawa, Makoto
PY - 2007/8
Y1 - 2007/8
N2 - The adsorption of Eu3+ from aqueous solution to natural Na+-montmorillonite (Kunipia F), synthetic saponite (Sumecton SA) and synthetic fluoro-tetrasilicic mica (Na+-TSM) clay samples was investigated. Adsorption capacities derived from the isotherms were 1.02, 0.71 and 1.00 meq/g of clay, respectively, for Kunipia F, Sumecton SA and Na+-TSM. The adsorption capacities were comparable to the cation exchange capacities of the clays, which were 1.19, 0.71 and 0.94 meq/g of clay, respectively. The greater slope of the TSM adsorption isotherm relative to the montmorillonite and saponite isotherms indicates a high affinity of Eu3+ for Na+-TSM. The high affinity of TSM for Eu3+ was thought to be related to the large electronegativity of the octahedral fluorine groups in TSM. Photoluminescence of adsorbed Eu3+ was observed for saponite and TSM, but not for montmorillonite. Quenching of Eu3+ luminescence by Fe in the montmorillonite structure is the probable reason for this phenomenon. The luminescence intensity varied with the amount of adsorbed Eu3+ for saponite and TSM as a result of self-quenching.
AB - The adsorption of Eu3+ from aqueous solution to natural Na+-montmorillonite (Kunipia F), synthetic saponite (Sumecton SA) and synthetic fluoro-tetrasilicic mica (Na+-TSM) clay samples was investigated. Adsorption capacities derived from the isotherms were 1.02, 0.71 and 1.00 meq/g of clay, respectively, for Kunipia F, Sumecton SA and Na+-TSM. The adsorption capacities were comparable to the cation exchange capacities of the clays, which were 1.19, 0.71 and 0.94 meq/g of clay, respectively. The greater slope of the TSM adsorption isotherm relative to the montmorillonite and saponite isotherms indicates a high affinity of Eu3+ for Na+-TSM. The high affinity of TSM for Eu3+ was thought to be related to the large electronegativity of the octahedral fluorine groups in TSM. Photoluminescence of adsorbed Eu3+ was observed for saponite and TSM, but not for montmorillonite. Quenching of Eu3+ luminescence by Fe in the montmorillonite structure is the probable reason for this phenomenon. The luminescence intensity varied with the amount of adsorbed Eu3+ for saponite and TSM as a result of self-quenching.
KW - Adsorption
KW - Europium (III) ion
KW - Fluoro-tetrasilic Mica
KW - Kunipia F
KW - Montmorillonite
KW - Photoluminescence
KW - Sumecton SA
KW - Synthetic saponite
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U2 - 10.1346/CCMN.2007.0550402
DO - 10.1346/CCMN.2007.0550402
M3 - Article
AN - SCOPUS:34848822487
VL - 55
SP - 348
EP - 353
JO - Clays and Clay Minerals
JF - Clays and Clay Minerals
SN - 0009-8604
IS - 4
ER -