土壤Cu~(2+)和Cd~(2+)的吸附解吸特征及差异分析

[目的]为了阐明重金属在不同类型土壤中的分布和迁移规律。[方法]用室内模拟法研究了农田、草地和林地不同类型土壤对Cu2+和Cd2+的吸附-解吸特征及差异。[结果]农田、草地和林地土壤对Cu2+的最大缓冲容量分别为833.332、71.43和500,对Cd2+的最大缓冲容量分别为75、12.5和21.43。对Cu2+的解吸率分别为8.25%、7.11%和5.06%,对Cd2+的解吸率分别为13.34%、13.66%和13.16%。[结论]土壤对Cu2+和Cd2+的吸附量随平衡液中离子浓度的增加而增加;农田土壤的饱和吸附量、吸附作用力、最大缓冲容量和吸附速率最大,但解吸率各类型土壤间差异不大;Cu2+比Cd2+更容易被土壤吸附,这与其本身化学性质有关;农田土壤吸附Cu2+和Cd2+能力比草地和林地土壤强,这与农田土壤的pH值、有机质、CEC和黏粒含量均高有关。

The Adsorption and Desorption Characteristics of Cu2 + and Cd2+ in Soil and the Difference Analysis

[Objective] The aim of study is to illuminate the distribution and migration rules of heavy metals in soil of different types to provide a scientific basis for preventing from the pollution of heavy metal [Method] By indoor simulation method,the adsorption-desorption characteristics difference of Cu2 and Cd2 in different soil types of farmland,grassland and forestland were studied.[Result] The maximum buffering capacity of Cu2 in farmland,grassland and forestland soils were 833.33,271.43 and 500 respectively.And the maximum buffering capacity of Cd2 were 75,12.5 and 21.43 respectively.The desorption rate of Cu2 were 8.25%,7.11% and 5.06% respectively,while the desorption rate of Cd2 were 13.34%,13.66% and 13.16% respectively.[Conclusion] The adsorption capacity of Cu2 and Cd2 increased with the increment of ion concentration in equilibrium liquid.The saturated adsorption amount,adsorption action force,the maximum buffering capacity and adsorption rate in farmland soils were the highest.And the desorption rate had little difference in soil of different types.The adsorption of Cu2 was much easier than Cd2 in farmland soils,which was related to its chemical properties.The adsorption capacity of Cu2 and Cd2 in farmland soils were higher than those in grassland and forestland soils,which was related to high pH value,organic matter,CEC and content of clay grain in farmland soils.