摘要
对不同浓度ＫＣＬ和不同ｐＨ下，３种可变电荷土壤和４种恒电荷土壤ＣＩ－吸附量进行了测定。结果表明，土壤ＣＩ－吸附量随平衡 ＣＩ－浓度 Ｃ（ｅ）增加而增大，恒电荷土壤呈线性，可变电荷土壤在添加 ＣＩ－ ０．５－５．０ ｍｍｏｌ／Ｌ．下，符合 Ｌａｎｇｍｕｉｒ吸附等温式。同一浓度下的ＣＩ－吸附量及其随浓度增加的速率均为砖红壤＞红壤＞赤红壤＞黄棕壤＞棕壤、暗棕壤和黑土，与这些土壤所带正电荷量顺序相一致。Ｌａｎｇｍｕｉｒ方程Ｋ值较小且几种土壤差异不大。恒电荷土壤对ＣＩ－的吸附量很小，在浓度较低时常出现负吸附，其吸附机理可能更多的是与Ｋ＋吸附时的同时吸附。７种土壤ＣＩ－吸附量均随ｐＨ增加而降低，但降低强度可变电荷土壤远大于恒电荷土壤。
The adsorption of chloride ions by three variable charge soils and four constant charge soils of China were measured under different pH and various concentrations of KCI. The results showed that although the amount of CI- adsorbed by soils increased with increasing CI- concentration, the linear relationship was only found in constant charge soils. For variable charge soils, within the range of 0.5 to 5 mmol/L of CI- added, the adsorption can be described by the Langmuir equation satisfactorily. And the adsorption energy parameter (K) calculated from the equation was similar in magnitude. When equal CI- added, the amount of CI- adsorption by different soils decreased in the sequence Latersol > red earth > red latersol > yellow brown earth > brown earth, dark brown earth and black soil, which was agreed with the order of their positive charges. The adsorption of chloride by constant charge soils, which caused by co-adsorption with K+ mainly, was a little and a negative adsorption was usually observed at low concentrations. The adsorption of CI- decreased with increasing with pH. However, the decreasing speed was higher in variable charge soils than that in constant charge soils.
出处
《土壤与环境》
CSCD
2001年第2期111-114,共4页
Soil and Environmental Sciences
基金
国家自然科学基金项目(49831005)
中国博士后科学基金项目
