| 恒电荷土壤及可变电荷土壤与离子间相互作用的研究 Ⅰ.共存离子对NO3-吸附的影响 |
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| 引用本文： | 徐明岗,季国亮. 恒电荷土壤及可变电荷土壤与离子间相互作用的研究 Ⅰ.共存离子对NO3-吸附的影响[J]. 土壤学报, 2001, 38(2): 204-211 |
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| 作者姓名： | 徐明岗 季国亮 |
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| 作者单位： | 徐明岗（中国科学院南京土壤研究所,南京210008）;季国亮（中国科学院南京土壤研究所,南京 210008） |
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| 基金项目： | *国家自然科学基金(49831005);中国科学院重点项目(KZ952-J1-204);中国博士后科学基金资助项目 |
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| 摘 要： | 研究了我国典型3种可变电荷土壤和4种恒电荷土壤在陪伴阳离子分别为K+、Na+、Ca2+时和1mmolL-1KCl、K2SO4支持电解质中NO-3的吸附.结果表明,NO-3吸附量随pH的增加而减小.在添加相同浓度NO-3时,3种可变电荷土壤对NO-3的吸附量顺序为Ca(NO3)2＞KNO3＞NaNO3＞KNO3+KCl＞KNO3+K2SO4;在初始NO-3浓度0.5～5mmolL-1的范围内,吸附量随浓度变化的关系符合Langmuir等温吸附式.由此求出与NO-3吸附结合能有关的常数(K)在不同共存离子存在下数值较小且差异不大,因此认为不同陪伴阳离子和不同伴随阴离子对NO-3吸附的电性机理影响不大,只是改变了土壤表面的正电荷数量从而使吸附量发生变化.4种恒电荷土壤对NO-3的吸附量通常很小,其中在Ca(NO3)2介质中较在其他介质中稍大,最大吸附量仅为1.5mmolkg-1左右,约为可变电荷土壤的1/10,且在浓度较低时常观察到负吸附.
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| 关 键 词： | NO3^－吸附 离子间相互作用 pH值 土壤电荷 电解质 恒电荷 |
| 收稿时间： | 2000-03-02 |
| 修稿时间： | 2000-03-02 |
STUDIES ON THE INTERACTION OF IONS WITH CONSTANTCHARGE SOILS AND VARIABLE CHARGESOILS |
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| Xu Ming-gang and Ji Guo-liang. STUDIES ON THE INTERACTION OF IONS WITH CONSTANTCHARGE SOILS AND VARIABLE CHARGESOILS[J]. Acta Pedologica Sinica, 2001, 38(2): 204-211 |
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| Authors: | Xu Ming-gang and Ji Guo-liang |
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| Affiliation: | Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008;Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 |
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| Abstract: | The adsorption of nitrate ions by three variable charge soils and four constant charge soils of China were measured under different pH, co-existing Cl- or S042- and accompanying K+,Na+ or Ca2+.The results showed that the amount of NOD adsorbed by soils decreased with increasing pH. For variable charge soils, the amount of adsorbed N03- in different electrolytes decreased in the order Ca(N03)2>KNO3>NaNO3>KN03+KCI>KN03+K2SO4.Within the range of 0.5 to 5 mmol L-1 of NOD added, the adsorption can be described by the Langmuir equation satisfactorily, and the adsorption energy parameter(K) as calculated from the equation was similar in magnitude when different anions and rations co-existed. This implies that the adsorption of NO3- is mainly determined by electric force, which can not be changed by such factors as the type and the concentration of co-existing rations and anions. These factors can only influence the adsorption of nitrate through changing the surface properties, mainly the quantity of positive charge of the soil. However, the adsorption of nitrate by constant charge soils was a little higher in Ca(NO3)2 Solution than that in other electrolytes. The maximum amount of adsorption by these soils was only 1.5 mmol kg-1,corresponding to about one tenth of the adsorbed N03- by variable charge soils. For these constant charge soils, a negative adsorption of NO3- was usually observed at low concentrations. |
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| Keywords: | Adsorption of nitrate ions Co-existing ions Accompanying rations pH |
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