Influence of Soil Type on Single and Competitive Retention Behavior of Inorganic Macro Cations in Binary as well as Ternary Solution

Inorganic macro cations (Na⁺, K⁺ and Ca⁺) co-exist in agricultural and municipal landfill sites. The retention behavior of these ions in different soils and combinations (binary and ternary system) has not been fully understood by previous studies. This study seeks to probe into the retention behavior of macro cations (Na⁺, K⁺, Ca⁺²) in six different soils under multiple combinations of ions solution. The retention of common ions was quantified by using Freundlich and Langmuir isotherms. Na⁺ (single) pollutant-soil interaction was desorbed in most of the soils. The retention of K⁺ and Ca⁺² was much greater than that of Na⁺. There is no definite trend for retention of Na⁺ in the presence of K⁺. For all soils, the retention results of K⁺ in the presence of Na⁺ decreased. Affinity for K⁺ was greater than that for Ca⁺² in most of the soils. This study also demonstrated the affinity sequence of the ion retention for each soil and the percentage reduction of ions in competition with respect to single ions. Anomalous trends of the isotherm parameter fitting suggested the limitation of the mathematical models in predicting the experimental data. These results can be helpful in improving accuracy of fate prediction of pollutant fate and thus, design of waste containment facilities for various wastes that contains inorganic ions.