Adsorption of lead (Pb) in strongly weathered tropical soil (Ribeira Valley region - Brazil)

Abstract

Lateritic soils have been widely used in the construction of landfill base liners for municipal and industrial waste. On the other hand, there is little practice in the use of strongly weathered residual soils for this finality. The use of local soil for the construction of liners in order to waterproof and retain contaminants represents an alternative to control this type of contamination. Thus, the objective of this study was to determine the physical and chemical properties of a strongly weathered tropical soil (residual soil) collected in the city of Eldorado Paulista (Ribeira Valley), and to evaluate the abilityof this soil to adsorb lead (Pb). The contamination of soil and water by Pb due to inadequate mining waste disposal is common in this region. The Pb was adsorbed by the residual soil, mainly at the lowest initial concentrations. When the initial concentration of 20 mg L-1 was used, the adsorption percentage of Pb was 92.5% and when the initial concentration was 100 mg L-1, the adsorption rate was 81.7%. In addition to the retention of Pb, this soil presented the following characteristics which are favorable for using soils in the construction of liners: fine granulometry, liquid limit (LL) of 57%, plasticity index (PI) of 33%, oxidizing medium and the predominance of negative charges on the surface of the colloidal particles. Thus, it is concluded that the weathered tropical residual soil exhibits characteristics that allow it to be used as a liner in the disposal of residues containing Pb.

Assessment of the use of tropical peats as local alternative materials for the adsorption of Pb, Zn and Cd: An equilibrium study

“…Pb, Zn and Cd are PTEs frequently present in areas contaminated by industrial and mining activities (Kasemodel et al, 2016;Marques et al, 2019). Pb is a toxic element that is nonessential and has the potential to accumulate in humans, affecting fundamental biochemical processes; it has the ability to imitate Ca and consequently inhibit Ca-protein interactions (ATSDR, 2007).…”