Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Metalorganic complexes as a major sink for rare earth elements in soils

Metalorganic complexes as a major sink for rare earth elements in soils Environmental contextThe role of rare earth elements in soilplant systems remains unclear. We use continuous-flow extraction, designed to mimic natural conditions while minimising artefacts, to study in vitro chemical fractionation of rare earth elements in soil. The study reveals a predominant association of rare earth elements and metal-organic complexes independent of soil type and contamination, and thereby provides valuable insights into the behaviour of these elements in soilplant systems.AbstractThe role of rare earth elements (REEs) in soilplant systems has attracted increasing attention but still remains somewhat unclear. Along invivo studies on the uptake of REEs by plants, invitro chemical fractionation of REEs in soil according to their physicochemical mobility can offer additional insights into the behaviour of REEs. In the present work, the fractionation of REEs was studied with the example of background, aerially and hydrogenically contaminated soil samples using dynamic (continuous flow) extraction, which allows natural conditions to be mimicked and artefacts to be minimised. The eluents applied addressed exchangeable, specifically sorbed, bound to Mn oxides, bound to metalorganic complexes, and bound to amorphous and poorly ordered Fe/Al oxides fractions extractable by 0.05M Ca(NO3)2, 0.43M CH3COOH, 0.1M NH2OHHCl, 0.1M K4P2O7 at pH 11, and 0.1M (NH4)2C2O4 at pH 3.2 respectively. The distribution of trace metals (such as Pb, Cu, Zn, Ni) between separated fractions varies with sample and is dependent on the type of contamination. However, for all samples, the recoveries of REEs by pyrophosphate are surprisingly high, up to 4045 of their total concentrations in background and anthropogenically transformed floodplain soils. As compared to metalorganic complexes, the contents of REEs bound to Fe/Al oxides are fairly low, no more than 12. REEs in other fractions may be taken into consideration only for aerially contaminated soil. Such a predominant association of REEs and metalorganic complexes (i.e. humic and fulvic compounds) independent of the type of soil has not been reported before. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Environmental Chemistry CSIRO Publishing

Metalorganic complexes as a major sink for rare earth elements in soils

Download PDF
10 pages

Loading next page...
 
/lp/csiro-publishing/metalorganic-complexes-as-a-major-sink-for-rare-earth-elements-in-EHDWUxVaCh

References (45)

Publisher
CSIRO Publishing
Copyright
Copyright © The Author(s). Published by CSIRO Publishing
ISSN
1448-2517
eISSN
1449-8979
DOI
10.1071/EN18275
Publisher site
See Article on Publisher Site

Abstract

Environmental contextThe role of rare earth elements in soilplant systems remains unclear. We use continuous-flow extraction, designed to mimic natural conditions while minimising artefacts, to study in vitro chemical fractionation of rare earth elements in soil. The study reveals a predominant association of rare earth elements and metal-organic complexes independent of soil type and contamination, and thereby provides valuable insights into the behaviour of these elements in soilplant systems.AbstractThe role of rare earth elements (REEs) in soilplant systems has attracted increasing attention but still remains somewhat unclear. Along invivo studies on the uptake of REEs by plants, invitro chemical fractionation of REEs in soil according to their physicochemical mobility can offer additional insights into the behaviour of REEs. In the present work, the fractionation of REEs was studied with the example of background, aerially and hydrogenically contaminated soil samples using dynamic (continuous flow) extraction, which allows natural conditions to be mimicked and artefacts to be minimised. The eluents applied addressed exchangeable, specifically sorbed, bound to Mn oxides, bound to metalorganic complexes, and bound to amorphous and poorly ordered Fe/Al oxides fractions extractable by 0.05M Ca(NO3)2, 0.43M CH3COOH, 0.1M NH2OHHCl, 0.1M K4P2O7 at pH 11, and 0.1M (NH4)2C2O4 at pH 3.2 respectively. The distribution of trace metals (such as Pb, Cu, Zn, Ni) between separated fractions varies with sample and is dependent on the type of contamination. However, for all samples, the recoveries of REEs by pyrophosphate are surprisingly high, up to 4045 of their total concentrations in background and anthropogenically transformed floodplain soils. As compared to metalorganic complexes, the contents of REEs bound to Fe/Al oxides are fairly low, no more than 12. REEs in other fractions may be taken into consideration only for aerially contaminated soil. Such a predominant association of REEs and metalorganic complexes (i.e. humic and fulvic compounds) independent of the type of soil has not been reported before.

Journal

Environmental Chemistry – CSIRO Publishing

Published: Apr 24, 2019

There are no references for this article.