摘要
为了解Cd、Pb在土壤中迁移转化规律,探明不同水稻土对Cd、Pb吸附解吸的影响,以红壤、紫色土母质发育的水稻土为对象,研究Cd、Pb在两种土壤中的吸附解吸行为,分析红壤、紫色土对Cd2+、Pb2+吸附解吸特性及其与土壤理化性质的关系。结果表明,两种土壤对Cd2+的吸附用Langmuir、Freimdlich模型均有较好拟合,相关系数在0.95以上;而Pb2+的吸附则用Freimdlich模型拟合较好,相关系数在0.99以上。随着溶液中Cd2+、Pb2+含量的增大,红壤、紫色土对Cd2+、Pb2+的吸附量增大;解吸量亦随吸附量的增加而增加。红壤、紫色土对Cd2+、Pb2+的最大吸附量分别为2871.34 mg/kg和4353.69 mg/kg,10914.65 mg/kg和14249.07 mg/kg;最大解吸率分别达到3.12%和2.43%,1.02%和0.33%。紫色土对Cd2+、Pb2+的吸附量大于红壤,解吸率低于红壤;同等浓度下,红壤、紫色土对Pb2+的吸附量高于Cd2+。研究表明土壤粘粒、有机质、CEC含量是影响红壤、紫色土吸附解吸差异的主要因素。
This study examined the characteristics of Cd and Pb adsorption-desorption in paddy soils （red and purple soils） and their relationships with soil physical and chemical properties. Results of this study could be beneficial for the understanding of Cd and Pb migration in soils and impacts of paddy soil types on Cd and Pb adsorption and desorption. The results showed that the adsorption data of Cd^2＋ could be simulated with both Langmuir and Freimdlich models （r 〉0.95）. In contrast, the adsorption data of Pb^2＋ could be simulated using the Freimdlich equation （r 〉0.99）. The adsorption capacities of two tested soil types both increased with the increasing concentrations of Cd^2＋, Pb^2＋. The desorption capacity was also on the increase in accordance to increased adsorption capacity. The maximum adsorption capacity of Cd^2＋-red soil, Cd^2＋-purple soil, pb^2＋-red soil and Pb2＋-purple soil were 2871.34 mg/kg, 4353.69 mg/kg, 10914.65 mg/kg and 14249.07 mg/kg, respectively. As a result, the maximum desorption rate reached 3.12%, 2.43%, 1.02% and 0.33% respectively. While the adsorption capacity of Cd^2＋ and pb^2＋ in the purple soil was greater than that of the red soil, the desorption rate was smaller. Furthermore, under the same heavy metal concentration, the adsorption of pbv2＋ in red soil and purple soil was higher than that of Cd^2＋. Soil clay, organic matter and CEC content were the major factors to control the differences of adsorption and desorption capacity between red and purple soils.
出处
《农业现代化研究》
CSCD
北大核心
2014年第5期663-667,共5页
Research of Agricultural Modernization
基金
国家环保部公益项目(201009047)
