电动力学-新型竹炭联合作用下土壤镉的迁移吸附及其机理  

Movement-Adsorption and Its Mechanism of Cd in Soil Under Combining Effects of Electrokinetics and a New Type of Bamboo Charcoal

作　　者：马建伟[1] 王慧[1] 罗启仕[2] 

机构地区：[1]清华大学环境科学与工程系环境模拟与污染控制国家重点联合实验室,北京100084 [2]上海市环境科学研究院,上海200233

出　　处：《环境科学》2007年第8期1829-1834,共6页Environmental Science

基　　金：国家重点基础研究发展规划(973)项目(2004CB418506);国家高技术研究发展计划(863)项目(2004AA64920)

摘　　要：研究了土壤中镉在均匀电动力学作用下的迁移特征及其影响因素，以及电场双向切换并加有新型竹炭材料条件下电动力学对镉的去除特性，揭示了利用均匀电动力学．新型竹炭材料联合修复镉污染土壤的特征及其可行性．结果表明，竹炭是一种良好的吸附材料，对镉具有较强的吸附作用，可以用Freundlich和Langmuir模型很好的模拟吸附过程（R^2〉0．96）；在电压梯度为1．0V／cm的条件下，受试土壤中Cd^2＋在均匀电动力学下的迁移速率为0．6786．0．6875cm／h，并且迁移速率大小与Cd^2＋浓度和场强分布有关，电动力场可以有效地迁移土壤中的重金属离子；使用竹炭作为吸附剂的新型工艺中，在与速率实验相同的电压梯度，电场48h的切换周期下，土壤中镉能够在电场作用下高效迁移至处理区并被吸附去除（12d去除79．6％），过程中可以很好地维持土壤的pH和水分条件，过程的电流随切换呈周期性的变化．电动迁移．竹炭吸附作为一种新型工艺具有广泛的应用前景．Tbe characteristics of migration and its influencing factor of cadmium in sandy loam soil by uniform electrokinetics as well as the adsorption property by a new material-bamboo charcoal were investigated through bench-scale experiments, and the legibility of using electrokinetic technique combined with the newly developed bamboo charcoal for remediation of cadmium contaminated soils was analyzed as well. The results show that the bamboo charcoal is good adsorption material which has comparably strong adsorption effect on Cd, bearing potential in future use, which could be simulated by both Freundlich and Langmuir models （R^2 〉 0.96）. The migration rates of cadmium in sandy loam were high up to 0.6786 - 0.6875cm/h under an electric gradient of 1.0V/cm, depending upon the concentration of cadmium and the distribution of electric field density. Elctrokinetics effectively transported the heavy metal in the soil. In the new electrokinetic tech combining the bamboo charcoal with the same electric gradient above under the polarity reversal period of 48 hours, the cadmium in the soil could be wiped off with high efficiency （removal efficiency 79.6% in 12 days） and the pH together with water content could be well retained. The electric current in the process changed periodically according to the reversal. As a new technique, the electrokinetic movement-bamboo charcoal adsorption holds high potential in future use.

关 键 词：电动力学 竹炭 镉 电迁移 双向切换 土壤修复 

分 类 号：X53[环境科学与工程—环境工程]