Mudstones as Landfll Liner Material for Heavy Metal Removal: Equilibrium and Dynamic Sorption Study

MUSSO, TELMA BELÉN; CARLOS, LUCIANO; PAROLO, MARÍA EUGENIA; FRANCISCA, FRANCO; PETTINARI, GISELA; GIULIANO, VALERIA; RUFFATO, MARIANELA

Water, Air & Soil Pollution

Springer

Año: 2022 vol. 233

Clay materials used as low-permeability barriers at landfll sites can also chemically attenuateinorganic contaminants (heavy metals) in leachate. In this study, Cu(II) removal capacity from aqueous media of a raw calcareous mudstone, used as a liner material, was evaluated through both batch and column tests. Batch experiments were conducted varying contact time, pH, and Cu(II) concentration. In order to simulate waste leachates composition, the effect of the presence of some organic compounds on Cu(II) uptake was also evaluated. Column tests of compacted calcareous mudstone-sand mixtures were performed to evaluate sorption in dynamic systems.The studied calcareous mudstone exhibited higher removal capacity in a wider pH range than a commercial Na-bentonite, which is a widely used heavy metal sorbent and clay liner . It was evidenced that calcite, an important component of the calcareous mudstone and found as very small and highly porous calcareous nannofossils, contributed to its sorption properties playing a signifcant role in t he Cu(II) removal. The presence of an anionic surfactant or phenol slightlyafected the removal of Cu(II). In the clay fraction (< 2 µm), Cu(II) sorption was favored by the presence of humic acids, which add new adsorption sites for this me tal. The extremely high retardation factor obtained for the raw calcareous mudstone is in good agreement with the high adsorption capacity experimentally proved in batch tests and demonstrated a great ability of this material to retain heavy metal mass during the transport in solution within porous media.