Electro-Phytoremediation of Cropland and Mine Tailings Polluted by Mercury, Using IrO 2 -Ta 2 O 5 /Ti Electrodes, Lavandula vera , and Solanum tuberosum

A circular arrangement of titanium electrodes, with six cathodes surrounding an anode at the center, was used to develop electrokinetic treatment (EKT) in the presence of ethylenediaminetetraacetic acid to remove mercury (Hg2+) from cropland and mine tailings, with application of 20 V for 72 h. The remediation included use of a permeable reactive barrier of Agave biomass sponge. Electro-phytoremediation (EKT + PhyR) with Lavandula vera was used to remove the mercury. After this treatment, the plants were sectioned into leaves, stems, and roots, and they were analyzed with atomic absorption spectroscopy for quantification of Hg2+ in their structure. In the mine tailing samples, the major concentrations were found in the stems and roots, whereas in the cropland samples, the major concentrations were found in the leaves. EKT + PhyR was also performed with Solanum tuberosum, which showed the capacity to bioaccumulate Hg2+ to generate enough bioelectricity (8.53 μW, 0.7993 V, and 51 μA) to power a light-emitting diode at 2.4 V.