Electro Phytoremediation with Innovative Methods in Soils Contaminated with Heavy Metals

Abstract

The reduction of the ecosystem's ability to renew itself due to human intervention has led to pollution of the air and water, as well as contamination of soil resources. Additionally, heavy metals present in soils are recognized as primary hazardous pollutants capable of exhibiting toxicity and carcinogenic effects due to their high density. The presence of these pollutants in the environment has always caused negative effects on the health of humans, plants, and animals.

Since the cleaning of contaminated soils using chemical and physical methods requires high economic costs, techniques considered as cheap alternatives are used instead. These techniques are phytoremediation, electro-phytoremediation, and electrokinetic methods, which involve the use of plants for the remediation of contaminated soils and have begun to be used for the removal of heavy metals. In this study, a total of 12 pots with different working conditions were set up with soils contaminated with Pb, Cd, Cr, Cu, and B elements: control 1 (phytoremediation), control 2 (electro-phytoremediation), control 3 (electrokinetic), and control 4 (sample specimens). For this purpose, canola plants were studied in soils with added Pb, Cd, Cr, Cu, and B elements using a periodic application of 30 V voltage and 4 hours of continuous DC current for 30 days. The use of graphite electrodes showed better removal of heavy metals. In the phytoremediation system with electrical stimulation, a moderate increase in pH was observed. The maximum amounts of lead and copper were obtained from the above-ground parts of the plants under electrical stimulation conditions, while the maximum amounts of chromium, cadmium, and boron were obtained from the roots. According to the results, plants stimulated by electrical current grew better and absorbed more metals. Based on the obtained results, the amounts of elements absorbed by the plants per kilogram of dry weight were determined using an ICP device. The results indicate that the electro-phytoremediation technique appears promising for the remediation of soils contaminated with heavy metals.