Geo-environmental Behaviour of Nanoclays in Interaction with Heavy Metal Contaminants

In recent years, the use of nanoclays in different projects are reported. However, there has been very little attention on the application of nanoclays in geo-environmental projects. In this paper the possibility of application of nanoclays for retention of heavy metal (HM) contaminant were investigated. To achieve this objective a series of experiments were performed on bentonite, kaolinite and nanoclays samples. The buffering capacity, retention properties and XRD experiments show that among Cation Exchange Capacity (CEC), specific surface area, and carbonate, the main factor that controls the soil-HM interaction is carbonate phase. The CEC is the second important factor. Furthermore, after interaction of soil samples with HM the intensity of basal spacing of minerals in XRD decreased. In Cloisite 15A which had the minimum interaction with HM, the minimum reduction in peak intensity was observed (200 Cps). In addition, the contaminant retention of soil samples are in accordance to following order: Bentonite> Cloisite®Na > Kaolinite> Cloisite®30B > Cloisite®20A > Cloisite®15A