Remediation of metal-contaminated marine sediments using active capping with limestone, steel slag, and activated carbon: a laboratory experiment

ABSTRACT

The objectives of this study are to assess the effectiveness of limestone (LS), steel slag (SS), and activated carbon (AC) as capping materials to sequester trace metals including As, Cd, Cr, Cu, Ni, Pb, and Zn in heavily contaminated marine sediments and to minimize the release of these metals into the water column. A flat flow tank was filled with 10 mm of capping material, contaminated sediments, and seawater, and the metal concentrations were monitored over 32 d. After completion of the flow tank experiments, the sediments below the capping material were sampled and were sequentially extracted. SS effectively reduced the As, Cr, Cu, Ni, Pb, and particularly Cd elution from the contaminated sediments to the overlying seawater. Adsorption and surface precipitation were the key mechanisms for interrupting the release of cationic trace metals by SS. LS was appropriate for interrupting the release of only Cu and Pb with high hydrolysis reaction constants. AC capping could interrupt the release of Cr, Cu, Ni, and particularly Zn from the sediments by binding with the metals via electrostatic interaction. The results obtained from the sequential extraction revealed that LS capping is appropriate for stabilizing Zn, whereas AC is appropriate for Cd and Pb. LS, SS, and AC can be applied effectively for remediation of sediments contaminated by trace metals because it interrupts their release and stabilizes the trace metals in the sediments.

GRAPHICAL ABSTRACT

KEYWORDS:

• Activated carbon
• active capping
• limestone
• steel slag
• trace metals

Acknowledgements

This work was supported by the project titled “Development of Sustainable Remediation Technology for Marine Contaminated Sediments” funded by the Ministry of Land, Transport, and Maritime Affairs, Korea. This research was also supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2017R1D1A1B03030649).

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Seong-Jik Park http://orcid.org/0000-0003-2122-5498

Additional information

Funding

This work was supported by the project titled “Development of Sustainable Remediation Technology for Marine Contaminated Sediments” funded by the Ministry of Land, Transport, and Maritime Affairs, Korea. This research was also supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education [No. 2017R1D1A1B03030649].