1. Introduction

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

2. Experimental procedure

Thetests can take soil was artificially contaminated with the HMs (lead, copper, nickel and zinc), and suspension adsorpn consideration tests were carried out to evaluate the adsorption capacityhe influence of 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 soil’s properties, reproducing in a better way the conditions similar toof a real on-sitefield situation. Leach

Sing tcests were also performed in order to verify if CNTs (the nanomaterial used) are not being releas all the options studied in the environment.

3. Results

Theis work results veallow to conclude that the additives, carbon nanotubes and montmorillonite , have the potential to minimize HMs mobility in contaminated soils and can bed to be technically efficient in the immobilization of heavy metals in soils, it may be concluded that MWCNTs and montmorillonite are a valid alternative to the usutraditional additive,on of Portland cement, even when tested in conditions similar to a real on-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 considercase scenario, unless stabilization the influence of the soil’s properties, reproducing in a better way the conditions of a real field situation.

Since all the options studied in this wo is also requirk revealed to be technically efficient in the immobilization of HMs in soils, the d. 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.

Full text: https://www.mdpi.com/2076-3417/10/22/7950 or Appl. Sci. 2020, 10, 7950; doi:10.3390/app10227950