Aluminum-Electrode-Based Electrocoagulation for Efficient Pb2+ ions and TOC Removal from Industrial Effluent: Performance to Techno-Economic Analysis

Abstract

The widespread contamination of industrial wastewater with lead (Pb²⁺) ions poses serious environmental and public health risks due to their toxic, teratogenic, carcinogenic, and mutagenic effects. In this study, an efficient electrocoagulation process (ECP) was explored for the treatment of real textile industrial effluent containing both organic and inorganic pollutants, including Pb²⁺ ions. An aluminium electrode-based electrocoagulation system (Al-ECP) was developed and identified as the most effective configuration for pollutant removal compared to other metal electrodes (Fe, Cu, and Zn) based ECP. The electrochemical processes occurring at the liquid-electrode interface were systematically examined along with long-term cycling stability to ensure electrode durability. Among the investigated electrodes, Al-ECP exhibited superior performance, achieving 98.5% colour removal, 82.8% Pb²⁺ ions removal, and 90.1% total organic carbon (TOC) reduction within 60 min at a current density of 50 mA cm^-2. Importantly, the TOC concentration decreased significantly from 307.8 mg/L to 30.29 mg/L, while the Pb²⁺ ion concentration was reduced from 520.0 mg/L to 89.0 mg/L. Besides, UV-Vis spectroscopic analysis has confirmed an efficient colour removal, attributed to the complexation and adsorption of pollutants with the in-situ generated amorphous Al(OH)₃ flocs. The successful capture of Pb²⁺ ions in the precipitated sludge was studied by X-ray photoelectron spectroscopy (XPS). Further, a techno-economic analysis has demonstrated the feasibility of the ECP system for industrial wastewater treatment and disinfection. Importantly, the study highlights its superior efficiency, stability, practical applicability, and that sludge generation was minimal in the Al-ECP system at low operating current densities. Furthermore, the Al electrode dissolution analysis based on Faraday’s law showed a Faradaic efficiency of 82.24% in effluent treatment. Overall, the findings demonstrate that the Al electrode based ECP is a promising, cost-effective, and scalable approach for sustainable industrial wastewater treatment.