Exchange Behaviour of Coen33 + on Soil and Peat Hymatomelanic Acids
| Main Authors: | U. K. PALU, S. K. CHAKRAVARTI |
|---|---|
| Format: | Article Journal |
| Bahasa: | eng |
| Terbitan: |
, 1988
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/6087686 |
Daftar Isi:
- Department of Chemistry, University of North Bengal, P. 0. North Bengal University, Darjeeling-784 430 Manuscript received 19 October 1981, revised 11 August 1988, accepted 17 August 1988 The exchange pattern or coen33+ on soil and peat hymatomelanic acids (SHy A and PHyA) resembles Langmuir type of curves and is dependent on pH; the stronger acidic group, e.g. COOH predominately participating in the interaction at lower pH. The release of Coen3+ from Coen3+- acid complexes exhibit that the orders of reactivity for monovalent cations are H >> Cs > Rb> K > Na ~ Li for Coea3 - SHyA system and H >> C3 > Rb > K > Na > Li for Coea3 -PHyA complex. The release isotherms for bivalent and organic cations indicate the following sequence of reactivity : Ba > Sr ~ Ca > Mg and (C2H5 )4 N > (CH3 )4 N. The reversals of exchangeability for Li and Na as well as for Ca and Sr are noticeable at lower concentration. The exchange isotherms with monovalent cations display that the exchange processes take place in three stages. The thermodynamic equilibrium constauts and Gibbs free energy changes for exchange reactions involving bivalent cations have been calculated by using Kielland's equation. The plots of logarithm of corrected selectivity coefficients or thermodynamic equilibrium constants against hydrated ionic radii and the reciprocals of the Debye- Huckel parameter ao , Indicate that the relative affinities of the ions for the exchanger substrates are much better correlated with ao rather than with ionic radii.