Remediation of metal-contaminated soils with the addition of materials – Part II: Leaching tests to evaluate the efficiency of materials in the remediation of contaminated soils

The effect of the addition of materials on the leaching pattern of As and metals (Cu, Zn, Ni, Pb, and Cd) in two contaminated soils was investigated. The examined materials included bentonites, silicates and industrial wastes, such as sugar foam, fly ashes and a material originated from the zeolitization of fly ash. Soil + material mixtures were prepared at 10% doses. Changes in the acid neutralization capacity, crystalline phases and contaminant leaching over a wide range of pHs were examined by using pHstat leaching tests. Sugar foam, the zeolitic material and MX-80 bentonite produced the greatest decrease in the leaching of pollutants due to an increase in the pH and/or the sorption capacity in the resulting mixture. This finding suggests that soil remediation may be a feasible option for the reuse of non-hazardous wastes.

► The effect of material addition on metal leaching is evaluated on soil–material mixtures.
► Changes in acid neutralization capacity and crystalline phases are examined in the mixtures.
► Metal leaching in mixtures is investigated within the 2–12 pH range.
► Sugar foam and zeolitic material, alone or combined, are proposed to reduce metal leaching.
► Soil remediation is a feasible option for the reuse of non-hazardous wastes.