Parametric study of cadmium and nickel removal from synthetic and actual industrial wastewater industry by electrocoagulation using solar energy

This study uses a solar-powered electrocoagulation process to examine the effect of experimental conditions on the removal of nickel (Ni) and cadmium (Cd) from synthetic and industrial wastewater. The results indicate that both metals were removed in 60 min. In addition, a neutral pH (6.9) has optimal removal performance for both metals. Additionally, improving the current density from 8 to 24 mA/cm2 reduces treatment times and enhances the removal efficiency to 87.2 % and 92.3 %. Also, incorporating potassium chloride (KCI) into the synthetic effluent enhances the electrical conductivity and the removal rates of heavy metals. For example, the removal efficiencies of Ni and Cd reach 98.8 % and 99.1 % with a KCI dose of 0.5 g.L−1. Using the electrocoagulation process for treating industrial wastewater indicates a considerable reduction in pollution, with a reduction in the total organic carbon (85.3 %) and key micronutrients (Cl−, NH4+, NO3−, and PO43−: over 74.9 %). Likewise, the concentration of heaviest metals, such as Cu, Pb, Zn, Cr, and Cd, was reduced by over 92.3 %. Scanning electron microscopy (SEM) validates the removal of the targeted metals, while X-ray diffraction (XRD) analysis of the recovered flocs shows the presence of aluminum hydroxides (Al(OH)3). Also, the SEM and XRD analyses show the presence of whitish deposits, largely gypsum, on the electrodes, with changed compositions and morphologies on the cathode and anode. This work shows that the solar-powered electrocoagulation process can be viewed as an effective way of removing heavy metals from wastewater, with the potential for optimization and industrial use under different experimental conditions. © 2025 Elsevier Ltd