Selective exchange of divalent transition metal ions in cryptomelane-type manganic acid with tunnel structure

1993 ◽  
Vol 8 (3) ◽  
pp. 611-616 ◽  
Author(s):  
Masamichi Tsuji ◽  
Sridhar Komarneni
Keyword(s):  
Ion Exchange ◽  
Transition Metal ◽  
Metal Ions ◽  
Adsorption Process ◽  
Tap Water ◽  
Transition Metal Ions ◽  
Distribution Coefficients ◽  
Tunnel Structure ◽  
Linear Relationships ◽  
Exchange Selectivity

The ion-exchange selectivity of divalent transition metal ions on cryptomelane-type manganic acid (CMA) with tunnel structure has been studied using the distribution coefficients (Kd) at a small fractional exchange in nitrate media. All metal ions studied showed linear relationships with a slope of −2 on the log-log plot of Kd vs [HNO3] which clearly indicated that the adsorption process is an “ideal” ion-exchange. The selectivity increased in the following order: Pb ≫ Mn > Co > Cu > Hg > Cd > Zn > Ni. The high selectivity of the manganic acid was successfully utilized in the removal of Co2+ from seawater and tap water.

Intermediate-stage transition metal ion exchange in a zeolite X

1982 ◽  
Vol 35 (7) ◽  
pp. 1335 ◽  
Author(s):  
M Chatterjee ◽  
D Ganguli
Keyword(s):  
Ion Exchange ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Intermediate Stage ◽  
Transition Metal Ions ◽  
Zeolite X ◽  
Counter Ions ◽  
Metal Ion Exchange ◽  
Exchange Behaviour

The exchange behaviour of some divalent transition metal ions M2+ (Zn2+, Cu2+, Ni2+, Co2+, Mn2+) in a zeolite NaX (SiO2/Al2O3 2.75) was studied at intermediate stages before equilibrium. The equivalent counter ion supply in the solution, given by the equivalent ratio of the two counter ions 2M2+/Na+, was found to be critical in determining the saturation level of exchange. The series of relative abilities of exchange was very similar to the well known selectivity series at equilibrium. It is suggested that water exchange of the metal ions in solution could be one of the factors controlling the relative ease of ion exchange.

Proton-insertion-pseudocapacitance of tungsten bronze tunnel structure enhanced by transition metal ions anchoring

Nanoscale ◽  
2021 ◽  
Author(s):  
Siwei Zhao ◽  
Chenlong Dong ◽  
Fu Qiang Huang
Keyword(s):  
Electron Transfer ◽  
Transition Metal ◽  
Metal Ions ◽  
Electrode Material ◽  
Tungsten Bronze ◽  
Transition Metal Ions ◽  
Tunnel Structure ◽  
Supercapacitor Electrode ◽  
One Dimensional ◽  
The One

The one-dimensional channel array of hexagonal tungsten bronze (WO3) offers an electron transfer matrix, but the overwhelming H+ adsorption hinders it to be a good supercapacitor electrode material. Inspired by...

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.

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