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Predicting cation exchange equilibria in soil containing three heterovalent cations
Author(s) -
Pal Raj,
Mehta S. C.,
Poonia S. R.
Publication year - 1983
Publication title -
zeitschrift für pflanzenernährung und bodenkunde
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 0044-3263
DOI - 10.1002/jpln.19831460508
Subject(s) - chemistry , ternary operation , adsorption , phase (matter) , ternary numeral system , mole fraction , activity coefficient , thermodynamics , equilibrium constant , inorganic chemistry , ion exchange , analytical chemistry (journal) , ion , chromatography , organic chemistry , aqueous solution , physics , computer science , programming language
Theoretical cation exchange equilibria relationships in a soil for a ternary system containing Na + , Ca 2+ and Mg 2+ are presented. The solid phase activity coefficients of cations for the three binary systems (i. e., Na + – Ca 2+ , Na + – Mg 2+ and Ca 2+ – Mg 2+ ) were used to calculate the Wilson parameters. Adsorbed phase activity coefficients of Na + , Ca 2+ and Mg 2+ corresponding to their equivalent fractions on the adsorbed phase of A horizon of a Camborthid for the ternary system (i. e., Na + – Ca 2+ – Mg 2+ ) were evaluated, using these Wilson parameters. Using the values of activity coefficients of adsorbed Na + , Ca 2+ and Mg 2+ in a ternary soil system and of thermodynamic equilibrium constants for the binary systems, the multiple linear regression relationships between the equivalent fractions of Na + , Ca 2+ and Mg 2+ on the adsorbed phase and their mole fractions in the equilibrium solution were obtained. The amounts of adsorbed phase cations so predicted showed a fair agreement with those observed experimentally in a ternary system.