A real scale phytoremediation of multi-metal contaminated e-waste recycling site with Eucalyptus globulus assisted by electrical fields.

The combined utilization of direct or alternating electric fields and phytoremediation was designed to decontaminate multi-metal polluted soil at a field scale e-waste recycling impacted site. Eucalyptus globulus was chosen for metal purification for its resilient and unpalatable nature. Biomass production, metal concentration and water use efficiency of the species under direct current (DC) and alternating current (AC) fields with various voltages were investigated. DC and AC fields stimulated the growth of the plant, except for DC field with high voltage (10 V). Metal concentrations increased in plant tissues under the influence of AC or DC fields irrespective of voltages. DC fields elevated the root and shoot metal contents of plants in equal proportions and AC fields tended to migrate metals from roots to the aboveground parts of the species. Compared to the control, soil moisture of various soil layers at the planted site was significantly lower and subsequently leading to the decrease of metal leaching. In soil profile metal distributes differently between DC and AC treatments. Compared to AC field, more metals tended to accumulate in soil surface under the influence of DC fields due to the stable converse gravitational pathway of metals. Considering decontamination efficiency, leaching interception and energy consumption, DC field with moderate voltage was a suitable candidate for real scale multi-metal polluted soil phytoremediation.
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