Am3+ and Eu3+ /alkali cation exchange selectivity on mordenite and zeolite L

2000 ◽  
Vol 15 (12) ◽  
pp. 2849-2856 ◽  
Author(s):  
Masamichi Tsuji ◽  
Hitoshi Mimura
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Selectivity Coefficient ◽  
Alkali Cation ◽  
Ionic Form ◽  
Alkali Cations ◽  
Ionic Radii ◽  
Zeolite L ◽  
Exchange Site ◽  
Exchange Selectivity

Am3+ and Eu3+ /alkali cation exchange selectivity was studied on mordenite and zeolite L at 25 to 60 °C to examine the effect of their openings of ion-exchange sites. The corrected selectivity coefficient at the infinitesimal exchange increased in the order of Eu3+ < Am3+ on mordenite and Am3+ < Eu3+ on zeolite L. The selectivity reversal did not reflect the effect of the ionic form, but reflected the dimension of the opening of the ion-exchange site and charge of trivalent cations, since the crystal ionic radii of alkali cations were much smaller than the openings of these zeolites (7–8 Å).

Cation Exchange Selectivity Coefficient Values on Smectite and Mixed-Layer Illite/Smectite Minerals

2009 ◽  
Vol 73 (3) ◽  
pp. 928-942 ◽  
Author(s):  
Christophe Tournassat ◽  
Hélène Gailhanou ◽  
Catherine Crouzet ◽  
Gilles Braibant ◽  
Anne Gautier ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Mixed Layer ◽  
Selectivity Coefficient ◽  
Exchange Selectivity

ESCA and Vibrational Spectroscopy of Alkali Cation Exchanged Manganic Acids with the 2×2 type Tunnel Structure Synthesized via Different Chemical Routes

2000 ◽  
Vol 658 ◽  
Author(s):  
Masamichi Tsuji ◽  
Hirofumi Kanoh ◽  
Kenta Ooi
Keyword(s):  
Ion Exchange ◽  
Vibrational Spectroscopy ◽  
Mixed Valence ◽  
Redox Process ◽  
Alkali Cation ◽  
Exchange Mechanism ◽  
Uptake Mechanism ◽  
Alkali Cations ◽  
Xrd Patterns ◽  
Mixed Valence Compounds

ABSTRACTManganese dioxides have received much attention over the last two decades as ion exchangers. Actually these are typically mixed-valence compounds and the terminology of ‘dioxide’ is not appropriate. The mechanisms for their variety of chemical reactivities are still open for study. On the cation uptake mechanism there are strong claims that a redox process is involved in cation uptakes by manganic acids synthesized by substituting H+ for alkali cations incorporated in ‘hydrous manganese dioxides’. The present work was carried out to physically demonstrate the alkali cation exchange mechanism on tunnel-structured manganic acids and to study the ion exchange with lattice vibrational spectroscopy. Manganic acids were prepared through the redox process using KMnO4 and MnSO4, and thermal decomposition of (CH3)3COK and MnCO3 at 530°C. ESCA spectra of their alkali cation exchanged forms indicated no evidence of redox process and supported the ion exchange mechanism on these materials. Their infrared absorption spectra strongly depended on their preparation routes and are closely related to their ion-exchange selectivity of each material. Thus, the vibrational spectra of manganic acids take an important role as a synthesis index together with XRD patterns.

Hofmeister Effects on Cation Exchange Equilibrium: Quantification of Ion Exchange Selectivity

2013 ◽  
Vol 117 (12) ◽  
pp. 6245-6251 ◽  
Author(s):  
Xinmin Liu ◽  
Hang Li ◽  
Wei Du ◽  
Rui Tian ◽  
Rui Li ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Exchange Equilibrium ◽  
Exchange Selectivity

Alginate Polyelectrolyte Ionotropic Gels-XII. Chromatographic Separation of Divalent Transition Metal Ions using Alginates as Ion Exchangers

1992 ◽  
Vol 4 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Refat M. Hassan ◽  
S. A. El-Shatoury ◽  
M. Th. Makhlouf
Keyword(s):  
Ion Exchange ◽  
Metal Ions ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Selectivity Coefficient ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Ion Exchangers ◽  
Calcium Alginate Gel ◽  
Exchange Selectivity

The separation of divalent metal ion mixtures has been investigated chromatographically on columns of either gel or sol forms of alginate polyelectrolyte. Separation was obtained in the form of narrow sharp zones for the metal ions. Ion exchange selectivity indicated that Cu2+ ions were most strongly retained among the divalent metal ions studied. The factors which affect the ion exchange selectivity, such as the strength of chelation and the mobility and radii of the metal ions, are discussed. The selectivity coefficient for the separation of a mixture of Cu2+ and Co2+ ions on columns of calcium alginate gel or sodium alginate sol was determined and found to be 1.9 ± 0.1 in both ion exchangers at 25°C.

Alkali metal ion exchange selectivity of Al-substituted tobermorite

1989 ◽  
Vol 4 (3) ◽  
pp. 698-703 ◽  
Author(s):  
Masamichi Tsuji ◽  
Sridhar Komarneni
Keyword(s):  
Ion Exchange ◽  
Alkali Metal ◽  
Cation Exchange ◽  
Separation Factor ◽  
Metal Ion ◽  
Infinite Dilution ◽  
Exchange Reactions ◽  
Alkali Metal Ion ◽  
Metal Ion Exchange ◽  
Exchange Selectivity

Alkali metal ion exchange isotherms at a total ionic strength of 0.001 M were determined at 25 °C on a 1.13 nm anomalous [Al3+ + Na+]-substituted tobermorite with the formula, Ca5Na0.75Al0.9Si5.1O16(OH)2 · 6.03H2O. The Kielland plots of Na+/K+, Na+/Rb+, and Na+/Cs+ exchange reactions showed straight lines. The slopes were steeper for Cs+ and Rb+ exchange reactions, as compared to K+ exchange. The cation-exchange selectivity for alkali metals was found to increase as follows: Cs+>Rb+>K+>Na+. A new evaluation method of the separation factor (αMN/KMd/KNd,Kd: distribution coefficient) for a combination of two cations at infinite dilution was proposed in terms of the selectivity coefficient (KMNa) which can be easily determined from the Kielland plot. An extremely large separation factor for Cs (αCsNa = 112) was found at infinite dilution. These basic studies of cation exchange selectivity are of relevance in cation separation and purification and nuclear waste disposal.

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