حذف سیانید از رسوب های سد باطله به وسیله فناوری الکتروکینتیک

There are known techniques for cyanide remediation from contaminated soil such as soil
washing, soil oxidation and biological degradation. However, there is very little research for
electrokinetic remediation of cyanide from soil.
This study investigates the application of electrokinetic remediation to contaminated soil with
high clay content and low coefficient of permeability. The experiments were conducted with
two electrodes as cathode and anode poles, which were placed inside the soil using the direct
electrical current. Thus cyanide ions were transported to the anode pole and caused the
remediation of the soil. The contaminated soil from tailing dam of Takab gold processing
plant was used. Contaminated soil with the concentration of 420 mg/kg, distilled water and
NaOH were employed in the electrokinetic cell.
The experiments were conducted on the optimum moisture content of clayed soil at two
voltage gradients (1.0 and 1.5 VDC/cm for the duration of 7 and 14 days) in order to assess
the effect of voltage gradient when employing 1M NaOH solutions and distilled water at the
anode pole. For each test, cyanide removal efficiency, the pH of the soil, moisture content,
electrical conductivity and the electrical current and flow were determined. The
measurements were conducted for the entire duration of electrokinetic experiments and at the
end of the test. The results indicated that the cyanide removal obtained in 7 and 14 days was
approximately 65% and 80%, respectively. The results also showed the pH of the soil was
changed from 8.83 to 1-2 for the anode and to 12-13 for the cathode pole. The cyanide
transported to the cathode and the pH were the most important dominant factors for cyanide
remediation.