Ca-K-Na Exchange Equilibria on a Smectitic Soil : Modeling the Variation of Selectivity Coefficient

概要

論文の詳細を見る
We conducted binary and ternary cation exchange experiments on a smectitic soil and calculated the Vanselow selectivity coefficients. The values of the natural logarithm of the Vanselow selectivity coefficients. The values of the natural logarithm of the Vanselow selectivity coefficient for Ca→Mg exchange, ln ^cK_<Mg/Ca>, slightly scattered around an average of -0.553. The values of ln ^cK_<K/Ca> and ^cK_<Na/Ca> in respective binary systems, on the other hand, significantly varied as the mole fraction of K in the exchanger phase increased. In the Ca-K-Na ternary system, ^cK_<K/Ca> varied in quite a similar manner as in the binary system whereas ln ^cK_<Na/Ca> behaved differently. Based on these observations, we modeled the variation of the selectivity coefficients using the data from ternary exchange experiments. The obtained equations are : ln ^cK_<K/Ca> = -4.271 N_K + 4.220, ln ^cK_<Na/K> = 2.417 N_K -2.742, and ln ^cK_<K/Ca> -ln ^cK_<Na/Ca> + 2ln ^cK_<Na/K>=0, where N_K is the mole fraction of K in the exchanger phase.
社団法人日本土壌肥料学会の論文