Effects of willow and Sedum alfredii Hance planting patterns on phytoremediation efficiency under AC electric field

Heavy metal contamination to soil is tricky due to its difficult removal, long retention time, and biomagnified toxicity. The green and low-cost phytoremediation with electric field treatment and planting pattern selection is an emerging and more effective approach to remove heavy metals from soils. In this study, alternating current (AC) electric field-assisted phytoremediation was examined with different planting patterns, i.e., monoculture willow (Salix sp.), monoculture Sedum alfredii Hance, and interplanting of willow and S. alfredii. AC electric field greatly increased phytoremediation efficiency to soil cadmium (Cd) regardless of planting patterns, either single plant species of willow or S. alfredii. The Cd removal capacity of willow and S. alfredii raises apparently under 0.5 V cm(-1) AC electric field. Under different planting patterns of AC electric field treatment, Cd accumulation in the whole plant by interplanting was 5.63 times higher than monoculture willow, but only 0.75 times as high as monoculture S. alfredii. The results showed that AC electric field-assisted interplanting of willow and S. alfredii is a promising remediation technique for efficiently clean-up Cd-contaminated soil.

Automated summary

This study investigated the remediation of heavy metal-contaminated soil using alternating current (AC) electric field-assisted phytoremediation. The results showed that AC electric field greatly enhanced the efficiency of phytoremediation for soil cadmium (Cd), regardless of the planting patterns. The interplanting of willow and Sedum alfredii showed the highest Cd accumulation in the whole plant, indicating its potential as an effective remediation technique.