The effects of different electric fields and electrodes on Solanum nigrum L. Cd hyperaccumulation in soil

Electrokinetics is a new attempt of strengthening hyperaccumulator Solanum nigrum L. Cd extraction. The effects of different electric fields and electrodes on S. nigrum accumulating Cd among of four electric field conditions (1 V cm(-1)) and two electrodes were determined. The results showed that the AC electric field significantly stimulated (p < 0.05) the growth of S. nigrum, and the biomass increased nearly by 40% compared with the control, while the DC electric field (including the switching polarity) had no significant effect. Electric field significantly increased (p < 0.05) Cd concentration in S. nigrum and the highest one was recorded for the DC electric field with switching polarity. S. nigrum Cd accumulation (ug pot(-1)) was the highest under the AC electric field, which was nearly 70% higher compared to the control. The innovation found was that the role of biomass enhancement for S. nigrum accumulating Cd (ug pot(-1)) was the first and increased Cd concentration was secondary under AC electrical field, which might be relative with S. nigrum is a weed species. Basically, there was no significant difference between the graphite and stainless steel electrode, but under AC electric field conditions, Cd accumulation of S. nigrum was significantly higher (p < 0.05) than stainless steel electrode, which is worthy of further revelation besides of statistic factor. In general, the accumulation (ug pot(-1)) of Cd by S. nigrum was the highest under the AC electric field, which was a very important reference for the electrokinetic conditions to be used in the practice of phytoremediation. (C) 2019 Elsevier Ltd. All rights reserved.