重金属铜离子在分层土壤中的迁移机制

以重金属铜离子为研究对象,设计了包含黏土防护层、壤土运移层、竹炭(碳粉)净化层组成的复杂室内大土柱(直径Φ=280 mm)模型。在重金属铜离子运移试验研究的基础上,着重分析了铜离子在具有复杂分层结构土柱模型中的迁移规律。结果表明,黏土对铜离子的吸附阻滞作用显著高于壤土,阻滞效率在91%左右。经黏土阻滞后,碳粉净化层与壤土层自净效率约占7.5%,显著降低了模型出口铜离子残余量(可降至总量的0.45%)。对设计研究模型,试验结果充分体现出黏土吸附阻滞作用为主、碳粉净化作用为辅的显著特性。因此,如将此理念推广至地下水环境保护实践,则可简称之为"以防为主,以治为辅"的地下水环境保护理念。

Investigation for the mechanism of copper ion migration regularity in layered soil

This paper is aimed at making an experimental investigation of the complicated clay soil column (Φ =280 mm) via an experimental model composed of the loam soil layer and the carbon powder purification layer in hoping to pursue the migration mechanism of the copper ions in such soils.The results of our investigation indicate that the migration velocity and the adsorption of the copper ions is closely related to such layered soils.As a resuit,we have found that the migration velocity of the copper ions in the loam soil tends to be faster than that in the clay soil with the adsorption power of the copper ions in the soil being stronger than that of the loam soil.On the other hand,the concentration of the copper ions has been found decreasing gradually with the increase of the soil depth.More exactly speaking,the adsorption inhibition effect of the clay soil turns out to be stronger than that of the loam soil with its retardation rate being so high as up to 91％.And,then,in the layer deeper than that layer,another 7.5％ of copper ions would also likely be absorbed by the carbon powder layer and the loam soil layer.Moreover,on the condition if the experiment can last till 70 days,it would be possible for the residual copper ions in group A to be absorbed at a rate of 2.78％ in the depth of 25 cm of the total loam layer,whereas the residual rate of the copper ions in group B can be reduced to 0.94％.It means that the residual rate of group A can be three times as much as that of group B.That is to say,the residual concentration of copper ions at the outer layer in group A and group B may turn to be 2.21％ and 0.45％ as that of the initial content,correspondingly,which implies that it is possible to reduce its residual concentration of the copper ions by nearly 5 times,so far as it can be expected.Thus,it can be said that,in reference to what we have done based on the adsorption effect of the clay soil and the purification effect of such layers,it would be possible to increase the removal rate of copper ions up to 99.55％.Seeing what we have done,the experimental results can be said fully representing the clay adsorption and purification effects of the carbon powder layer as a remarkable auxiliary characteristic feature.Therefore,if the idea can be extended to the environmental protection practice for the groundwater,it would be possible to formulate and popularize a theory in reference to as "giving superiority to prevention,that the groundwater environmental protection concept can be taken as that of the auxiliary one".