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Thursday, June 23, 2016

ElectroHorticulture and Phytotechnologies Reduce Heavy Metals in Soil

3 Electrokinetic coupled Phytotechnology articles that support the ElectroHemp phytoremediation techniques the team has developed.
Taking it one step further by growing the plants in a greenhouse ensures that cross contamination and public exposure is eliminated. see the ElectroHemp BioRad Disposal Info


Electrokinetic enhancement on phytoremediation in Zn, Pb, Cu and Cd contaminated soil using potato plants
Coupled electrokinetic remediation–Bioremediation

Electrokinetic enhancement on phytoremediation in Zn, Pb, Cu and Cd contaminated soil using potato plants

Abstract

The use of a combination of electrokinetic remediation and phytoremediation to decontaminate soil polluted with heavy metals has been demonstrated in a laboratory-scale experiment. Potato tubers were planted in plastic vessels filled with Zn, Pb, Cu and Cd contaminated soil and grown in a greenhouse. Three of these vessels were treated with direct current electric field (DC), three with alternative current (AC) and three remained untreated as control vessels. The soil pH varied from anode to cathode with a minimum of pH 3 near the anode and a maximum of pH 8 near the cathode in the DC treated soil profile. There was an accumulation of Zn, Cu and Cd at about 12 cm distance from anode when soil pH was 5 in the DC treated soil profile. There was no significant metal redistribution and pH variation between anode and cathode in the AC soil profile. The biomass production of the plants was 72% higher under AC treatment and 27% lower under DC treatment compared to the control. Metal accumulation was generally higher in the plant roots treated with electrical fields than the control. The overall metal uptake in plant shoots was lower under DC treatment compared to AC treatment and control, although there was a higher accumulation of Zn and Cu in the plant roots treated with electrical fields. The Zn uptake in plant shoots under AC treatment was higher compared to the control and DC treatment. Zn and Cu accumulation in the plant roots under AC and DC treatment was similar, and both were higher comparing to control. Cd content in plant roots under all three treatments was found to be higher than that in the soil. The Pb accumulation in the roots and the uptake into the shoots was lower compared to its content in the soil.


Abstract

Electrokinetic-assisted phytoremediation is an innovative technology to decontaminate heavy metal contaminated soil. In this study, the effect of electric current on plant growth and speciation of soil heavy metals has been investigated by pot experiments, and the remediation processes of electrokinetic-assisted phytoremediation has been discussed. After Indian mustard (Brassica juncea) grew for 35 d, four voltage gradients (0, 1, 2, 4 V cm−1) of direct-current (DC) were applied timely (8 h d−1) across the soils for 16 d. The extractable soil metals by different extraction methods had a significant redistribution from the anode to the cathode after the treatments. Simple correlation analysis indicated that the correlation coefficients of the extractable soil metals with root metals were better than that with shoot metals. Plant uptake of metals increased by the electrokinetic-assisted phytoremediation, and a medium voltage gradient of 2 V cm−1 was the best due to the highest metal accumulation in the plant. Voltage gradient was the most important factor in affecting the plant growth, soil properties and metal concentrations in the soil and plant.

Graphical abstract

Image for unlabelled figure

Highlights

► We study the change of soil properties in different soil sections after experiments. ► Impact mechanism of the combined technique on metal uptake by plant is investigated. ► The extractable soil metals has a significant redistribution form anode to cathode. ► The highest metal accumulation of plant is in the treatment of 2 V cm−1. ► Voltage is the foremost factor in affecting the metal contents in soil and plant.

Key words

  • Electrokinetic-assisted phytoremediation
  • Heavy metals
  • Indian mustard
  • Chemical speciation
Corresponding author. Tel.: +86 25 86881180; fax: +86 25 86881000.


Effects of electrokinetic-assisted phytoremediation of a multiple-metal contaminated soil on soil metal bioavailability and uptake by Indian mustard  (Citations: 1
Electrokinetic-assisted phytoremediation is an innovative technology to decontaminate heavy metal contaminated soil. In this study, the effect of electric current on plant growth and speciation of soil heavy metals has been investigated by pot experiments, and the remediation processes of electrokinetic-assisted phytoremediation has been discussed. After Indian mustard (Brassica juncea) grew for 35d, four voltage gradients (0, 1, 2, 4Vcm−1) of direct-current (DC) were applied timely (8hd−1) across the soils for 16d. The extractable soil metals by different extraction methods had a significant redistribution from the anode to the cathode after the treatments. Simplecorrelation analysis indicated that the correlation coefficients of the extractable soil metals with root metals were better than that with shoot metals. Plant uptake of metals increased by the electrokinetic-assisted phytoremediation, and a medium voltage gradient of 2Vcm−1 was the best due to the highest metal accumulation in the plant. Voltage gradient was the most important factor in affecting the plant growth, soil properties and metal concentrations in the soil and plant.