A series of experimental batch tests has been carried out with the aim of improving the knowledge of fundamental processes related to the fate and behavior of heavy metals that can be of environmental concern in groundwater. The analysis of contaminants (i.e., Cu, Zn, Cd and Pb) dynamics in different environmental compartments is specifically addressed by comparing the removal efficiencies of different types of reactive materials, three natural (i.e., vegetal fibers, natural limestone and natural zeolite) and one synthetic (i.e., synthetic zeolite). Results stemming from these reactive media has been compared with the outcomes related to the same test performed using zero valent iron which is the reactant usually employed for heavy metals remediation. All tested reactants exhibited important removal percentages, even larger than 90% in most cases, achieved in a contact time ranging between about 12 h and slightly longer than a day (i.e., 30 h). Maximum adsorption percentages are observed for pH ranging between 4 and 8 for all tested materials and contaminants. Our findings provided relevant evidence, to both researchers and technicians, on the competitiveness of the explored alternative mediums with respect to the classical reactants usually employed for heavy metals remediation.
Keywords: batch test; contaminants dynamics; heavy metals in groundwater; natural fibers; zeolite; zero valent iron.