Speciation of rare earth elements

The speciation of rare earth elements and the interest in the topic arose due to the need for such information in the case of actinides. Both sets are f elements and the need... 

Zhang, S., Shan, X.-Q., 2001. Speciation of rare earth elements in soil and accumulation by wheat with rare earth fertilizer application. Env. Poll. 112, 395 05. 

Wang, Q., Huang, B., Guan, Z., Yang, L., and Li, B., Speciation of rare earth elements in soil by sequential extraction than HPLC coupled with visible and ICP-MS detection, Fresenius J. Anal. Chem., 370, 1041, 2001. 

Land, M., Ohlander, B., Ingri, J., Thunberg, J., 1999. Solid speciation and fractionation of rare earth elements in a spodosol profile from northern Sweden as revealed by sequential extraction. Chem. Geol. 160, 121-138. 

In addition, there exist a multitude of different applications in water analysis by ICP-MS for environmental control. For example, Lawrence et cdP determined rare earth element concentrations in natural waters (these are river, lake, sea or groundwater) by quadrupole ICP-MS using external calibration and employed river water reference material SLRS-4 to validate the analytical data. The speciation of yttrium and lanthanides in water samples by SEC-ICP-MS was studied by Haraguchi et a/.18 whereby the detection of La, Ce and Pr corresponded to the occurrence of large organic molecules. 

The rare earth elements in the parent rocks associated with minerals are fairly resistant to weathering. But to the extent the weathering of rare earth minerals occurs, rare earths are released as M3+ ions. In the case of minerals containing Sm2+ and Eu2+ the ions are easily oxidized to trivalent state and their further speciation depends on the following secondary reactions. In principle meteoric water is capable of setting free rare earth ions or as a soluble M3+ complex. 

Clay Mineralogy. Hydrothermal Vent Deposits. Platinum Group Elements and their Isotopes in the Ocean. Pore Water Chemistry. Rare Earth Elements and their Isotopes in the Ocean. River Inputs. Tracers of Ocean Productivity. Transition Metals and Heavy Metal Speciation. Uranium-Thorium Decay Series in the Oceans Overview. 

An additional major speciation assessment provided a greatly improved, comprehensive view of inorganic complexation in seawater. Based on the analogous characteristics of metal complexation by carbonate and oxalate, Turner et al. concluded that rare earth element complexation in seawater is dominated by carbonate. Subsequently, as the result of approximately twenty years of progress in seawater speciation, the Principal Species assessment of Bruland listed seventeen elements with carbonate-dominated Principal Species. 

Wood, S.A. (1990a) The aqueous geochemistry of the rare-earth elements and yttrium. 1. Review of available low-temperature data for inorganic complexes and the inorganic REE speciation of natural waters. Chem. Geol., 82, 159-186. 

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