The influence of operational parameters on elimination of cyanide from wastewater using the electrocoagulation process

The electrocoagulation process (ECP) was investigated for the removal of cyanide from wastewater in batch and continuous operation under different conditions. The batch experiments indicated that an iron–aluminum electrode arrangement as anode–cathode attained the highest removal efficiency. The increase of the current densities of 2 to 15 mA/cm2 resulted in an increase of cyanide removal from 43% to 91.8% after 20 min of reaction in the absence of aeration. Under similar conditions, aeration of the reactor enhanced removal efficiencies from 45% to 98%. Continuous operation of the ECP reactor with various hydraulic retention times (HRT) led to an increase of cyanide removal from 57% at an HRT of 15 min to complete elimination at an HRT of 140 min. Thus, we conclude that electrocoagulation is a cost-effective promising process for efficient treatment of cyanide-laden wastewater.

► The efficacy of the electrocoagulation (EC) was evaluated to remove CN−?.
► Batch tests indicated that a Fe-AL electrode as anode–cathode attained the highest CN−?removal.
► The increase of the current density to 15 mA/cm2 increased the removal of CN−to 98%.
► Continuous tests showed that the EC could completely eliminate 300 mg/L CN−at an HRT of 140 min.