Comparison of different extracting agents for the recovery of Pb and Zn through electrokinetic remediation of mine tailings. (1st February 2021)

• Record Type: Journal Article
• Authors: Asadollahfardi, Gholamreza; Sarmadi, Mohammad Sina; Rezaee, Milad; Khodadadi-Darban, Ahmad; Yazdani, Mahdie; Paz-Garcia, Juan Manuel
• Is Part Of: Journal of environmental management. Volume 279(2021)
• Publication Date: 2021-02-01
• Subjects: Electrokinetic remediation -- Mine tailings -- Heavy metal -- Electrolyte conditioning -- Pre-treatment; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2020.111728
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: This study was conducted to investigate the feasibility of Electrokinetic Remediation to remove lead and zinc from real mine tailings, collected from the Lacan's lead and zinc Mineralized Flotation Processing Plant (Markazi province, Iran). High buffering capacity, high organic matter, and heavy metal contamination were the unique characteristics of this mine tailing. Electrokinetic remediation of the mine tailings was carried out in 11 separate experiments under constant voltage gradient of 2 V/cm for 9 days. Various enhancement techniques were tested, such as 1) electrolyte conditioning using chelating agents including ethylenediaminetetraacetic acid, citric acid, acetic acid, and hydrochloric acid; 2) increasing the concentration of the catholyte solution, and 3) adding chelating agents to the soil as a pre-treatment of the tailings and the electrolyte condoning simultaneously. The concentration of each electrolyte solution was selected based on the different extraction tests that resulted in the optimal or highest extraction percentage of lead and zinc. Electrolyte conditioning, in the case of using citric acid 1 M enhanced the removal of Pb and Zn dramatically. Catholyte conditioning, using citric acid 1 M, was the most effective enhancement technique for removing Zn (38.34%); also, the best removal efficiency of Pb (51.31%) was achieved using the same electrolyte solution in both electrode chambers. Increasing the acetic acid concentration was favorable for removal of both heavy metals. Compared to catholyte conditioning, pre-treatment coupled with catholyte conditioning could not improve the removal efficiency considerably. Graphical abstract: Image 1 Highlights: Electrokinetic remediation was performed in real contaminated mine tailings with high buffering capacity. Maximum removal of ≈ 51% lead and ≈ 38% zinc achieved using citric acid as the electrolyte. Increasing acetic acid concentration from 1 to 3 M favored Pb and Zn removal efficiency. Pre-treatment coupled with catholyte conditioning was not a favorable enhancement technique.