Enhance electrokinetic remediation of potentially toxic elements in the dredged sediment of Camorim Lagoon

Remediação eletrocinética de elementos potencialmente tóxicos de sedimentos da lagoa de Camorim

ABSTRACT

Electrokinetic remediation, effective for low-permeability sediments, can remove both organic and inorganic contaminants simultaneously. This study investigated its application to dredged sediments from Camorim Lagoon (Jacarepaguá lagoon complex, Rio de Janeiro), known to be contaminated with potentially toxic metals (chromium, copper, lead, zinc, and nickel). A buffer solution controlled pH changes, while the complexing agent ethylenediaminetetraacetic acid (EDTA) and humic substances aided metal desorption and removal. Treatments utilizing EDTA (EK2 and EK3) achieved lower final concentrations of zinc and lead. Notably, EK1 (freshwater only) achieved the lowest nickel concentration observed in the anodic section. EK1 also achieved the lowest copper concentration; however, none of the treatments reached regulatory limits for copper. Chromium, which is the least mobile metal, is concentrated in the middle section for all treatments, suggesting the need for further electrolyte optimization to promote efficient chromium transport.

Keywords:
electrokinetic remediation; potentially toxic elements; dredged sediment; pH control; circular economy