TIntroduction

Since heavy study revealed that even if the adsorpmetals (HMs) are not biodegradable and cannot be destroyed through high temperatures or the use of chemicals, ordinary soil remediation testchniques are a valid tool to evaluate the performance of the additives, only percolation tesineffective. One of the most promising techniques to immobilize heavy metals consists of mixing additives with the soil with the objective to reduce the potential migration of HM and thus the risk of contaminating adjacent areas.

Experimental procedure

The soil was artsificially can take in consideraontaminated with the HMs (lead, copper, nickel and zinc), and suspension adsorption the influenceests were carried out to evaluate the adsorption capacity of the soil’s properties, reproducing in a better way the additives (CNTs and clay mineral). Percolation tests were then conducted to better evaluate the efficiency of CNTs, clay mineral, and Portland cement to immobilize the HMs tested, in the soil, in conditions ofsimilar to a real fieldon-site situation.

S Leachincg tests were all the options studiso performed in order to verify if CNTs (the nanomaterial used) are not being released in this worke environment.

Results

The revesults aled to be technically efficient in the immobilization of heavy metals in soils, it may be concluded that MWCNTllow to conclude that the additives, carbon nanotubes and montmorillonite , have the potential to minimize HMs mobility in contaminated soils and montmorillonite arcan be a valid alternative to the traditionausual addition of ve, Portland cement even , when tested in conditions similar to a real case scenario, unless stabilizon-site situation. Moreover, the study revealed that even if the adsorption tests are a valid tool to evaluate the performance of the additives, only percolation tests can take in consideration the influence of the soil is also’s properties, reproducing in a better way the conditions of a real field situation.

Since rall thequired. T options studied in this work revealed to be technically efficient in the immobilization of HMs in soils, the designers’ and decision-makers’ choice of the best additive will depend mainly on the environmental-economic compromise.

Figure 1 - Results from the adsorption tests. Individual adsorption of lead (a), copper (b), nickel (c) and zinc (d) by the soil, MWCNTs and suspension of soil with the addition of MWCNTs.

Figure 2 - Results from the percolation tests. Immobilization of heavy metals by the soil, the soil with Portland cement and the soil with Portland cement with MWCNTs/montmorillonite.