Insight into the electrochemical process of EDTA-assisted soil washing effluent under alternating current

• Published in: Journal of hazardous materials Vol. 470; p. 134115
• Main Authors: Huang, Jiating, Xiao, Xin, Chen, Baoliang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.05.2024
• Subjects: Alternating current; Dual-chamber electrolytic cell; EDTA recycling; Heavy metal removal; Soil washing effluent; Soil washing effluent; Heavy metal removal; EDTA recycling; Dual-chamber electrolytic cell; Alternating current
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.134115

EDTA has been widely utilized as a chelating agent in soil heavy metal remediation, due to its strong coordination capability. Electrochemical deposition is a promising avenue to treat soil washing effluent. However, the impact of advanced electrochemical techniques on EDTA remains incompletely understood. Herein, we present a pioneering approach, utilizing a dual-chamber electrolytic cell and alternating current (AC) power supply. This approach achieves concurrent removal of M-EDTA while efficiently recovering heavy metal and recycling EDTA. Results demonstrate AC displays superior heavy metal removal capability for Cu, Pb, and Cd compare to direct current (DC), with EDTA decomposition mainly occurring in the anolyte. Substituting DC with AC and employing the dual-chamber electrolytic cell significantly enhances EDTA recovery efficiency from 47% to an impressive 96.8%. XPS and Raman spectra reveal an enhanced oxidative surface of the graphite anode under AC, which diminishes the decomposition of EDTA. Long-term experiments validate that this strategy boosts EDTA cyclability to 20 cycles with an outstanding 84% recovery efficiency and negligible electrode corrosion, surpassing the 8 cycles under the traditional strategy. This study innovatively combines cell design and electrochemical techniques, remarkably improving the reusability of EDTA and anode, offering valuable insights for chelate-related applications. [Display omitted] •AC displays superior heavy metal removal capability for Cu, Pb, and Cd.•Both the dual-chamber electrolytic cell and AC power supply was employed.•The recovery rates of EDTA increased from 47% to an impressive 96.8%.•The graphite anode mitigates the decomposition of EDTA under AC.•The application of AC slows down the corrosion of the graphite anode.