- Study on the relationship between Cl- and Cd2+ in soil solution on Different Soil Types
- 摘要：土壤Cd的环境行为与其在土壤溶液中的存在形态以及陪伴离子有关,然而外源Cl-与土壤溶液中Cd2+的关系以及不同母质土壤对Cd的环境行为的影响并没有明确的结论。选取2种水稻土(第四纪红色黏土母质发育的红黄泥、紫色砂页岩母质发育的紫泥田)为研究对象,添加外源Cd(0、1、2.5、5 mg.kg-1),平衡老化后添加外源Cl(0、0.6、1.2 mg.kg-1),在保持水分恒定的情况下进行模拟培养试验,研究外源Cl-添加对土壤溶液Cd2+浓度的影响。结果表明,随着外源Cd含量的增加,土壤溶液Cd2+的浓度提高,红黄泥土壤溶液Cd2+的浓度显著高于紫泥田；添加Cl-会使土壤溶液中Cd2+浓度升高,且Cd2+浓度与外源Cl-呈显著正相关,红黄泥和紫泥田土壤溶液中Cd2+的平均浓度比不添加Cl-时Cd2+的平均浓度分别增加了12.74 %、51.49 %；土壤对Cd的吸附关系符合Freundlich等温吸附方程,紫泥田对Cd2+的吸附量显著高于红黄泥,添加Cl-对红黄泥Cd2+的吸附影响很小,而对紫泥田的影响显著。Cl-存在下,红黄泥和紫泥田的解吸率分别为12.50 %~19.25 %、14.76 %~24.99 %,外源Cl-添加对Cd2+解吸影响小。综合分析认为,Cl-对不同土壤Cd2+的吸附解吸行为影响有较大的差异。
- Abstract：The environmental behavior of soil Cd is related to its presence in soil solution and accompanying ions. However, the relationship between exogenous Cl- and Cd2+ in soil solution and the environmental behavior of Cd in different parent materials have no clear conclusions. Two kinds of paddy soils (reddish clayey soil developed from quaternary red clay parent materials and purple paddy field developed from purple sandy shale parent materials) were selected as research objects, and exogenous Cd 0, 1, 2.5, 5 mg?kg-1 was added to balance. After aging, exogenous Cl 0, 0.6, 1.2 mg?kg-1 were added, and the simulated culture experiment was carried out while keeping the water constant. The effect of exogenous Cl- addition on the concentration of Cd2+ in the soil solution was studied. The results showed that with the increase of exogenous Cd content, the concentration of Cd2+ in soil solution increased, and the concentration of Cd2+ in reddish clayey soil solution was significantly higher than that in purple paddy field. Adding Cl- would increase the concentration of Cd2+ in soil solution, and the concentration of Cd2+ and The exogenous Cl- showed a significant positive correlation. The average concentration of Cd2+ in the soil solution of reddish clayey soil and purple paddy field increased by 12.74 % and 51.49 % respectively than that without Cl-, the adsorption relationship of soil to Cd accorded with Freundlich isotherm. Adsorption equation, the adsorption amount of Cd2+ in purple paddy field is significantly higher than that of reddish clayey soil. The addition of Cl- has little effect on the adsorption of reddish clayey soil Cd2+, but has a significant effect on purple paddy field. In the presence of Cl- the desorption rates of reddish clayey soil and purple paddy field soil were 12.50 %~19.25 % and 14.76 %~24.99 %, respectively. Exogenous Cl- addition had little effect on Cd2+ desorption. According to the comprehensive analysis, the effect of Cl- on the adsorption and desorption behavior of Cd2+ in different soils is quite different.