Dynamics of Fe, Mn, and Al liberated from
contaminated soil by low-molecular-weight
organic acids and their effects on the release of
soil-borne trace elements

Qin, J; Enya, O; Lin, C

Abstract

A 15-day batch experiment was conducted to investigate the behaviours of Fe, Mn, and
Al oxides upon attack by three common low-molecular-weight organic acids, and their effects on
liberation of trace elements from a multi-contaminated soil. While the capacity of malic acid to
mobilize soil-borne Fe, Mn, and Al was weaker compared to citric and oxalic acids, a similar trend
was observed, showing that the concentration of dissolved Fe, Mn, and Al increased with increasing
duration of the experiment. Marked increase in metal concentrations only took place after 5 or 7 days
of the experiment. For the same organic acid treatment, Fe, Mn, and Al all showed a very similar
temporal variation pattern. The concentration of dissolved Fe, Mn, and Al was markedly controlled
by the total Fe, Mn, and Al contained in the soil, respectively. It appears that manganese oxides
were more reactive to the organic acids, as compared to their Fe and Al counterparts. However,
when multiple organic acids were present, the soil-borne Fe, Mn, and Al were mobilized rapidly
within the first 5 or 7 days of the experiment and then tended to decrease. The formation of insoluble
Fe, Mn, and Al organic complexes tended to be enhanced due to co-existence of multiple organic
acids, resulting in the re-immobilization of the dissolved Fe, Mn, and Al. The organic acid-driven
dissolution of Fe, Mn, or Al had a major control on the mobilization of As, Cr, Zn, Ni, Cu, and Cd
that were bound to these oxides with a correlation coefficient being frequently greater than 0.9 for As,
Cr, Zn, and Ni.

Citation

soil-borne trace elements. Applied Sciences, 8(12), 2444. https://doi.org/10.3390/app8122444

• Journal Article Type: Article
• Acceptance Date: Nov 28, 2018
• Online Publication Date: Dec 1, 2018
• Publication Date: Dec 1, 2018
• Deposit Date: Dec 7, 2018
• Publicly Available Date: Dec 7, 2018
• Journal: Applied Sciences
• Publisher: MDPI
• Volume: 8
• Issue: 12
• Pages: 2444
• DOI: https://doi.org/10.3390/app8122444
• Publisher URL: https://doi.org/10.3390/app8122444
• Related Public URLs: https://www.mdpi.com/journal/applsci