【摘要】 应用砖红壤、红壤、黄棕壤和两种粘土矿物,根据用玻璃电极所测得的离子活度计算了土壤对钠和钾离子的结合能,结果发现:1.当悬液中的离子数量相等时,固相的电荷愈多,结合能愈大。2.当保持固相的电荷量相等时,离子量愈少,则结合能愈大。3.无论是可变电荷的比例很大的砖红壤,还是可变电荷的比例很小的膨润土或不含可变电荷的强酸型阳离子交换树脂,pH 对结合能都有强烈的影响。作者根据实验材料认为,土壤体系中局部的电场强度较整个体系的平均体积电荷密度在决定离子的结合能方面具有更大意义;在 pH 低时,氢铝离子对交换点的竞争是钾、钠离子的结合能减小的一个重要原因.更多还原

【Abstract】 For the purpose of calculating the bonding energies of sodium and potassium ions in relation to the electric charge of soils,cation activities of the suspension in equilibrium with various types of soils or clays carrying different electric charge were measured with glass electrode.It was found that for the same soil type the bonding energy was a func- tion of the relative proportion of the clay concentration to the total concentration of cations in the system.The bonding energy of a lateritic soil was changed when the soil particles were coated with a layer of ferric oxides so as to alter their electric charge. Changes of bonding energy were also found when the cation-exchange capacity of a ben- tonite clay was decreased by thermal treatment.With respect to the soil type,it was shown that the bonding energies of the yellowish brown earth were almost double that of the lateritic soil.The pH of the medium affected the bonding energy markedly, even for the bentonite clay or cation-exchange resin with little or no variable electric charge. Evidences seem to favour the assumption that at lower pH the competition of aluminum and hydrogen ions for exchange sites is one of the important factors in causing the decrease of the bonding energy of alkali metal ions.It was suggested that Coulomb’s force is a decisive factor in inducing the interaction between the cations and the electric charge of soil particles,and in this respect the local electric field strength on clay particles seem to be more important than the mean volume charge density of the whole system.更多还原