Int. Journal of Renewable Energy Development 10 (3) 2021: 415-424 Page | IJRED-ISSN: 2252-4940.Copyright © 2021. The Authors. Published by CBIORE 415 Contents list available at IJRED website Int. Journal of Renewable Energy Development (IJRED) Journal homepage: http://ejournal.undip.ac.id/index.php/ijred Copper and Lead Ions Removal by Electrocoagulation: Process Performance and Implications for Energy Consumption Aji Prasetyaningrum * , Dessy Ariyanti, Widayat Widayat, Bakti Jos Department of Chemical Engineering, Faculty of Engineering, Diponegoro University, Jl. Prof. Soedarto S.H., Tembalang, Semarang 50275, Indonesia. ABSTRACT. Electroplating wastewater contains high amount of heavy metals that can cause serious problems to humans and the environment. Therefore, it is necessary to remove heavy metals from electroplating wastewater. The aim of this research was to examine the electrocoagulation (EC) process for removing the copper (Cu) and lead (Pb) ions from wastewater using aluminum electrodes. It also analyzes the removal efficiency and energy requirement rate of the EC method for heavy metals removal from wastewater. Regarding this matter, the operational parameters of the EC process were varied, including time (20−40 min), current density (40−80 A/m 2 ), pH (3−11), and initial concentration of heavy metals. The concentration of heavy metals ions was analyzed using the atomic absorption spectroscopy (AAS) method. The results showed that the concentration of lead and copper ions decreased with the increase in EC time. The current density was observed as a notable parameter. High current density has an effect on increasing energy consumption. On the other hand, the performance of the electrocoagulation process decreased at low pH. The higher initial concentration of heavy metals resulted in higher removal efficiency than the lower concentration. The removal efficiency of copper and lead ions was 89.88% and 98.76%, respectively, at 40 min with electrocoagulation treatment of 80 A/m 2 current density and pH 9. At this condition, the specific amounts of dissolved electrodes were 0.2201 kg/m 3, and the energy consumption was 21.6 kWh/m 3 . The kinetic study showed that the removal of the ions follows the first-order model. Keywords: Heavy metals; electrocoagulation; energy consumption; kinetics; copper; lead Article History: Received: 16 th July 2020; Revised: 15 th Dec 2020; Accepted: 20 th January 2021; Available online: 17 th February 2021 How to Cite This Article: Prasetyaningrum, A., Ariyanti, D., Widayat, W., Jos, B. (2021) Copper and Lead Ions Removal by Electrocoagulation: Process Performance and Implications for Energy Consumption. Int. Journal of Renewable Energy Development, 10(3), 415-424. https://doi.org/10.14710/ijred.2021.31665 1. Introduction The metal coating industry disposes of large amounts of liquid wastewater that contains a variety of hazardous and toxic heavy metals, namely alkaline cleaning agents, oil, fat, copper, chromium, nickel, cyanide, zinc, and degreasing solvents (Akbal and Camcı 2011; Hunsom et al. 2005; Prasetyaningrum et al. 2019). If they are released into the environment with no treatments, most of those metals can harm the environment. Common methods such as chemical, physical, and biological processes can be utilized to treat heavy metals present in wastewater. Those methods include the utilization of NaOH in the precipitation process and Al2(SO4)3 or FeSO4 in the coagulation process with subsequent time-consuming sedimentation, ion exchange, biosorption, precipitation, adsorption, reverse osmosis, filtration, and membrane collection (Reverberi et al. 2014; Adhoum et al. 2004; Tchobanoglous et al. 2003). The precipitation method is a simple and common process to remove the heavy metals in wastewater. Basically, this method is conducted using chemical coagulants, mostly aluminum or iron salts, to convert the * Corresponding author: aji.prasetyaningrum@che.undip.ac.id pollutants into colloidal material and regulate the pH of wastewater (Agridiotis et al. 2007). However, that method produces byproducts as secondary pollutants that may harm the environment (Shahedi et al. 2020). One of the promising process to treat heavy metal content in the wastewater is electrocoagulation (EC). Compared to the other methods, there are several points of interest of the EC process, such as: having high-quality effluents, low energy consumption, low dissolved solids, and low sludge formation (Moradi et al. 2021; Samsami et al. 2020; Chen 2004; Zhu et al. 2005). In addition, it is very environmentally compatible, versatile, cost-effective (Cotillas et al. 2014), and provides opportunities to apply inherent safety principles (Fabiano et al. 2014) without executing strict safety standards (Abrahamsen et al. 2013). During the EC process, no chemicals were included to form coagulant. Besides, it was governed by the electric field, generally direct current (DC) charges, to the wastewater solutions through sacrificial electrodes made of iron or aluminum (Akbal and Camcı 2011; Shahedi et al. 2020; Chen 2004). The air is oxidized to produce oxygen gas and hydrogen ions (H + ) due to the difference in Research Article