Selectivity and effectiveness of extractants used to release metals associated with organic matter

Applied Geochemistry
By: , and 

Links

Abstract

Partial extraction procedures can be used to release metals associated with organic matter in natural materials. Reagents commonly employed for this purpose include hydrogen peroxide, Na hypochlorite and Na pyrophosphate. This study tested the selectivity of these reagents by comparing the amount of Fe, Mn, Zn and Cu they released from sulfide and oxide minerals and determined the ability of these reagents to release the same metals from peat. Sodium hypochlorite and Na pyrophosphate released between 0.2 and 8.7% of the total metal content of the Fe, Cu and Zn minerals. In contrast, three commonly used hydrogen peroxide reagents released significantly more metals from the oxides and sulfides. Percentages of Zn and Mn released from the peat samples were comparable for all extractions tested. Per cent Cu released from peat by Na pyrophosphate was very low compared to that released by hydrogen peroxide/HNO3 or na hypochlorite. A smaller fraction of Fe was released from peat by Na hypochlorite than by the other reagents. Iron release by Na hypochlorite correlates with the organic carbon content of the peat samples. A universal extractant for metals associated with organic matter in all types of samples has not been identified. Sodium hypochlorite and Na pyrophosphate are better than hydrogen peroxide in selectively releasing metals bound to organic matter because they do not release significant amounts of metals from oxide and sulfide minerals.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Selectivity and effectiveness of extractants used to release metals associated with organic matter
Series title Applied Geochemistry
DOI 10.1016/0883-2927(91)90010-M
Volume 6
Issue 3
Year Published 1991
Language English
Publisher Elsevier
Contributing office(s) Toxic Substances Hydrology Program
Description 5 p.
First page 349
Last page 353