Restoration of Cadmium Contaminated Soil Using Approaching Anode Method of Polygonal Electrode

Yushan Wan, Anwei Wang, Meng Shen

Ekoloji, 2019, Issue 107, Pages: 1041-1047, Article No: e107123

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Abstract

In order to explore the effect of moving anode polygonal electrodes in restoring cadmium contaminated soil, the cadmium contaminated soil was prepared at laboratory and a regular hexagon electrode electric restoration experimental device was set up in this study. The repair effect of fixed anode method and approaching anode method was compared and analyzed under the condition of constantly shortening the distance between anode and cathode and the electric field strength being 2 V·cm-1. The results showed that the current variation trend of the fixed anode method was similar to that of the approaching anode method. The variation of pH value of both was basically the same, and the decrease trend of pH value of approaching anode method was significant at the later stage of restoration. After 120 h of electric restoration, for both cases, the content of Cd residue near the anode and in the middle of the soil chamber changed slightly, while that near the cathode increased; the weak acid extraction state and reducible state of Cd near the anode and in the middle of the soil chamber decreased significantly than that before the restoration. The removal rate of Cd at type A2 sampling points by fixed anode method was 68%, and the removal rate of Cd at these points was 95% by approaching anode method. The energy consumption of the approaching anode method was reduced by 65% compared with that of the fixed anode method. The approaching anode method is more effective.

Keywords

electrokinetic restoration, cadmium pollution, soil, approaching anode method, energy consumption

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