摘要
研究了SO2-4添加顺序对三种可变电荷土壤(昆明铁质砖红壤、徐闻砖红壤和江西红壤)吸附Cu2+的影响,作为对照,也研究了其对恒电荷土壤(黄棕壤、棕壤)以及两种不同矿物(高岭石与针铁矿)吸附铜离子的影响。实验结果表明,在同等条件下,SO2-4添加顺序对两类表面性质不同的土壤吸附Cu2+有着不同的影响。对于恒电荷土壤,SO2-4添加顺序对土壤吸附Cu2+几乎没有影响。同等pH条件下,对可变电荷表面而言,加入CuSO4者具有最高的Cu2+吸附率;对昆明砖红壤、徐闻砖红壤以及针铁矿和高岭石而言,先加入Cu2+者相对先加入SO2-4者Cu2+吸附率更高;对江西红壤而言,上述这个次序则刚好相反。SO2-4浓度和有机质去除对同等pH条件下铜离子吸附率高低的排序并无实质性影响。
To investigate effect of sequence of sulfate addition on adsorption of Cu2＋ by soils, samples of variable charge soils （Ali-Haplic Acrisol from Jinxian, Rhodic from Xuwen and Hyper-Rhodic from Kunming） , constant charge soils （ Haplic Luvisol from Nanjiug and Brown soil from Weihai） , geothite and kaolinite were used in the experiment. All the samples, except kaolinite, were treated with electrodialysis. Copper ion was spiked at a rate of 1 cmol L-1, and sulfate at a rate of 0. 1 cmol L-1 and 1 cmol L-1, separately. The experiment was designed to have three treatments in sequence, that is, Treatment 1 ： addition of copper nitrate, stand, vibration and addition of sulfate; Treatment 2： addition of copper sulfate and nitrate the same time, stand and vibration; and Treatment 3 ： addition of sulfate, stand, vibration and addition of copper nitration. All the samples were treated to keep copper ions and sulfate the same in concentration in the suspensions before vibration in the end. Soil pH of the samples was measured with glass electrodes, and copper ions measured with Atomic Adsorption Spectrometry. Results show that the effect of sequence of sulfate addition on Cu~~ adsorption by soils varied from soil to soil different in surface charge properties. For constant charge soils, the sequence of sulfate addition did not have much effect on Cu2＋ adsorption. On the other hand, among the three treatments, when pH was kept the same, variable charge soils, kaolinite and goethite in Treatment 2 were the highest in Cu2＋ adsorption rate. For All - Haplic Acrisol, the samples in Treatment 3 were higher than those in Treatment 1 in Cu2＋ adsorption rate. For Hyper-Rhodic Ferrasol, Rhodic Ferrasol, kaolinite and geothite, the effect was just the opposite to that on Ali-Haplic Acrisol when they were under the same condition. No matter on what samples, application rate of sulfate did not have any effect on the order of the treatments in Cu： ~ adsorption rate, and a similar phenomenon was observed when Hyper-Rhodic Ferrasol was deprived some of its organic matter. It is generally accepted that anions may affect soil adsorption of coexisting cations in three ways： （1） ion strength; （2） specific adsorption; （3） ion pairing. As in the end, the anions and cations in the suspension are the same in type and concentration, the effect of ion strength on Cu2＋ adsorption should not have any difference. Although specific adsorption of sulfate will lead to release of hydroxyl, thus altering Cu2＋ adsorption electrochemical properties of the suspension, the comparison of the treatments in was done under the condition that the suspensions were the same in pH. In this experiment, the only factor causing differences between the soils in Cu2＋ adsorption might be the complexing reaction of sulfate and copper ions with soil surface. After careful consideration of the findings in the experiment and the differences in surface electrochemical properties between the soils used in the experiment, it can be concluded that the causes of the differences between the soils in Cu2＋ adsorption should be the complexing reaction of copper ions and sulfate with soil sulfate, and the difference between variable charge soils and constant charge soils in surface charge properties.
出处
《土壤学报》
CAS
CSCD
北大核心
2014年第4期860-867,共8页
Acta Pedologica Sinica
基金
广东省财政专项资金项目(粤财农[2013]563号
[2012]471号)
广东省科技厅科技攻关项目(2012B030800007)
广东省农业科学院博士启动基金资助
作者简介
邹献中（1968-），男，湖南怀化人，博士，副研究员，主要从事土壤化学方面研究丁作。E-mail：patroonkiller@sina．com
通讯作者，E-mail：yshaoh@21cn．com
