Characterization of sludge generated by electrocoagulation for the removal of heavy metals
Year: 2013
Type: article
Abstract: In this work, heavy metal removal by electrocoagulation (EC) was evaluated, and the characteristics of the EC sludge were investigated to understand the behavior of heavy metals during EC. It was found that iron electrodes are superior to aluminum due to the negatively charged surface. Using iron electrodes, the removal rate of heavy metals increased as the current density increased and as the total initial heavy metal amount, either single or multiple heavy metals, decreased, suggesting that the efficiency is closely related to the floc amount. The X-ray diffraction (XRD) patterns showed that the chemical species in the EC sludge are different from those obtained by chemical equilibrium analysis, indicating that many electrochemical and chemical reactions occur during EC. The pH variation during EC and the XRD patterns of the sludge indicate that precipitation, adsorption, and chemical oxidation/reduction in the vicinity of the electrodes contribute much to Pb(II), Cd(II), and Cu(II) removal, respectively. In addition, the formation of Pb(OH)Cl, β-Cd2(OH)3Cl, and CuCl was found, indicating that chloride from the background electrolyte contributes to heavy metal precipitation. Scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis also showed that Pb(II) and Cu(II) are encapsulated by the flocs.
Source: Desalination and Water Treatment
Authors: Do-Gun Kim, Ronna Jane S. Palacios, Seok-Oh Ko
Institution: Kyung Hee University
Language: English
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,000
OpenAlex ID: W2090937339