凹凸棒石用于修复铜锌镉重金属污染土壤的研究

利用凹凸棒石黏土矿物优异的物化性能对采集的安徽铜陵地区重金属污染土壤进行盆栽修复试验,以降低种植蔬菜中重金属污染物的有效态含量。凹凸棒石与矿区土壤的质量配比设置5组(1∶10、1∶20、1∶40、1∶100以及原土),选择适宜在北京生长的四季小白菜和北京快菜进行种植,盆栽试验结果表明,使用凹凸棒石黏土矿物可以将土壤的pH值提高到5～8,改善了矿区的土壤环境条件,提高黏土矿物对重金属的吸附性能;通过适量添加凹凸棒石黏土矿物,对Cu元素的平均修复率达到31.50%,Zn元素的平均修复率达到26.15%,Cd元素的平均修复率达到34.92%,能够有效减少蔬菜对Cu、Zn、Cd三种重金属元素的吸收。凹凸棒石与土壤的质量比为1∶20时,对污染土壤的修复效果最佳。

Remediation Experiments of Attapulgite Clay to Heavy Metal Contaminated Soil

In order to reduce the heavy metals in vegetables, the excellent physical and chemical abilities of attapulgite clay were applied to potting remediation experiments on heavy metal contaminated topsoil sampled from Tongling city, Anhui province. The proportions of attapulgite clay to contaminated topsoil were 1:10, 1:20, 1:40, 1:100 plus one sample containing only contaminated topsoil. The small Chinese cabbage and Beijing fast cabbage were chosen as the test plants. The potting remediation experimental results indicate that the pH of the potting soil improved from 5 to 8, therefore improving the condition of the soil and increasing the adsorbability of attapulgite clay for heavy metals. Adding different amounts of attapulgite clay to these two kinds of vegetables, the average repair rates of Cu, Zn and Cd were 31.50%, 26.15% and 34.92%, respectively. The best proportion of the attapulgite and topsoil is 1:20 which provides optimum results for improvement to contaminated topsoil.