Electrokinetic Remediation of Chromium-Contaminated Puliyantangal Lake Sediments in India and the Effect of Bone Dust Amendment in Chromium Removal

Abstract

Soil contamination, particularly by chromium from industrial effluents, remains a significant global environmental concern. Contaminant removal stands out as a pressing requirement in the current environmental landscape. The increased levels of these contaminants underscore the urgency for effective removal measures. This study focuses on the electrokinetic remediation of chromium-contaminated soil collected from Puliyantangal Lake, Ranipet, Tamil Nadu. Investigating the effects of supply voltage and bone dust amendment on chromium removal efficiency, the research sheds light on the details of this emerging in situ remediation technique. The results indicate that the optimal removal efficiency of hexavalent chromium [Cr(VI)] was achieved at 15 V with a maximum removal of 66.97%. Increased voltage enhanced Cr(VI) remediation through electromigration, while the dissociation of bone dust constituent (hydroxyapatite) positively impacted the removal process through chromium (III) hydroxide [Cr(OH)3] deposition and elevated Cr(VI) reduction. Furthermore, the study reveals a synergistic reduction in total chromium content through electromigration and chemical reduction of chromium species under direct current source application. The decreasing trend of Cr(VI) content from cathode to anode was observed for both 15 and 30 V, with enhanced reduction at higher voltages. Interestingly, the combination of bone dust amendment showed superior Cr(VI) removal efficiency at 15 V, emphasizing the significance of the relationship between voltage and amendment effectiveness. This unique interaction between hindered electromigration and enhanced Cr(VI) reduction holds promise for optimizing electrokinetic remediation strategies, providing valuable insights for future environmental remediation studies.