Simultaneous removal of lead and cyanide from the synthetic solution and effluents of gold processing plants using electrochemical method

Hazardous effluents containing heavy metals and toxic compounds such as cyanide are among the contaminants produced annually by mining activities. In this study, the electrocoagulation method was used to simultaneously remove cyanide and lead from the synthetic and natural effluents of a gold mine processing plant. The effect of four parameters including initial pH, current intensity, reaction time, and electrode arrangement was investigated under different conditions. Results indicated that by increasing the current intensity to 300 mA at pH = 9 for 40 min, the cyanide and lead removal efficiencies were increased to 91% and 74%, respectively. In addition, the highest cyanide and lead removal efficiencies at pH = 9 and a current intensity of 300 mA after 40 min were 97% and 81%, respectively. The removal of 100% of cyanide in the presence of lead using Fe as the anode electrode can be attributed to the higher oxidation rate of iron than aluminum and the formation of more flocs in the solution The removal of 94% of lead in the presence of cyanide using aluminum as the anode electrode can be related to pH limitations applied for the simultaneous removal of lead and cyanide as well as the dissolution of aluminum species at this pH, preventing its complete removal. Overall, it can be concluded that the electrocoagulation method is an effective technique for simultaneous removal of lead and cyanide from contaminated effluents.

Automated summary

The study showed that the electrocoagulation method can effectively remove cyanide and lead from gold mine effluents, with the removal efficiency increasing under specific conditions. Parameters such as current intensity, pH, and reaction time were found to be crucial factors affecting the removal efficiency.