亚表层土壤修饰改性对镉离子的吸附影响

Effects of Modification of Sub-Top Lou Soil on Cd^(2+) Adsorption

采用室内试验方法,研究了不同比例CTMAB单一修饰和CTMAB+SDS混合修饰的亚表层对金属镉离子的吸附影响。结果表明,吸附量顺序为CK>50%CTMAB>100%CTMAB≥120%CS,最佳吸附等温线模型可以用BET模型描述。热力学参数的研究表明,吸附自发性与吸附量具有相同的变化规律,反应的熵变对于反应的自发性具有决定作用。土样修饰改性后镉离子吸附的自发性减小,活性增加,淋溶性及对地下水的危害性增大。

A study was done to reveal Cd 2+ adsorption on sub-top Lou soil(clay layer)modified with CTMAB at various ratio s and with CTMAB +SDS mixture.The results showed that the order of adso rption a mount of Cd 2+ was CK>50%CTMAB >100%CTMAB≥120%CS,and the adsorbed amounts in creased with temperature rise.In addition,the BET model was the best model tha t can be used to describe the Cd 2+ adsorption isotherm.The results of thermodynamic parameters indicate d that the spontaneity of Cd 2+ adsorption on modified soils had the same sequence with Cd 2+ adsorption amount and was mainly man ipulated by entropy.The modification r esulted in decrease o f Cd 2+ adsorption spontaneity,the enhancement of activity of Cd 2+ ,and the increase of both eluviating ability of Cd 2+ and endangerment for groundwater.T he present investigation gives the t heo retical evidence for the hazard evaluation of eluviation &transport of heavy me tals on modified sub-top soil.