Techno-economic assessment of Ni removal from industrial wastewater by electrocoagulation using rectangular aluminium electrodes

The present research focuses on the removal of nickel Ni(II) from synthetic and industrial wastewater using rectangular aluminium electrodes. The main effect of electrocoagulation (EC) parameters to remove heavy metals in a batch electrolytic reactor was evaluated and the characteristics of the EC sludge were investigated to understand the behaviour of nickel during EC. The electrocoagulation process was applied to assess the effect of electrochemical parameters such as: initial pH (pH(i)), current density (j), electrolyte concentration [NaCl], electrolysis time t(EC) and connection mode on removal efficiency of Ni(II), energy consumption, flow structure and treatment cost. The results indicated that maximum nickel removal was obtained with a bipolar connection, initial pH = 5.0, current density j = 1.388 mA cm(-2), electrolysis time t(EC) = 30 min and [NaCl] = 1.5 g L-1. At optimal conditions, nickel removal reached over 95.51% with an energy consumption of barely 0.195 kWh m(-3). Once electrocoagulation performance was determined, economic treatment cost of the process was evaluated. In this way, a useful economic feasibility indicator is obtained, and it has been possible to show the effectiveness of this process in the treatment of industrial waste water with a total removal of Ni(II) and a low treatment cost. In the light of these results, this method promises interesting industrial applications.

Automated summary

This research focuses on the use of rectangular aluminum electrodes to remove nickel from synthetic and industrial wastewater. The study evaluates the effects of electrocoagulation parameters on heavy metal removal and investigates the behavior of nickel during the process. The results show that optimal conditions for maximum nickel removal include a bipolar connection, pH of 5.0, current density of 1.388 mA cm(-2), electrolysis time of 30 minutes, and NaCl concentration of 1.5 g L-1. The process achieves over 95.51% nickel removal with minimal energy consumption of 0.195 kWh m(-3). The economic feasibility of the process is also evaluated, showing its effectiveness in treating industrial wastewater with total nickel removal and low treatment cost. These findings suggest potential industrial applications for this method.