Distribution and source determination of rare earth elements in sediment collected from the continental shelf off Hainan Island, China

Abstract Contents of rare earth elements (REEs), major elements and the Total Organic Carbon (TOC) were determined for 152 surface sediment samples collected from the continental shelf off Hainan Island (CSHI). From high to low, the average contents of REEs were: Ce > La > Nd > Pr > Sm > Gd > Dy > Er > Yb > Eu > Ho > Tb > Tm > Tm. The concentrations of REEs in the north of the study area were higher than in the south. The LREE concentrations in the south were higher than in the north. This resulted higher values for the LREE/HREE ratio in the south than in the north. The mean EF could be arranged from highest to lowest as follows: Tm > Sm > Pr > Er > La > Lu > Ce > Tb > Eu > Nd > Yb > Gd > Ho > Dy. The enrichment factor (EF) indicates that pollution as a result of human activity was more serious in the southeast of the study area than in the north. The factors affecting the REE concentrations in this area include naturally occurring minerals and industrial pollution. Based on the spatial variation of upper continental crust (UCC)-normalized REE concentrations, the CSHI was classified into three geochemical provinces. The sediment of province I was controlled by the Red and Pearl rivers. The composition of the province II is mainly controlled by the Red River and the Pearl River, although some sediments have originated from the South China Sea Island. Province III sediments mainly originated from sources on Hainan Island.

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USE OF A PORTABLE X-RAY FLUORESCENCE DETECTOR FOR DETERMINATION OF RARE EARTH ELEMENTS IN COAL BYPRODUCTS

10.1130/abs/2016am-286373 ◽

2016 ◽

Author(s):

Elliot Roth ◽

◽

Tracy L. Bank ◽

Emma Keegan ◽

Evan Granite

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Fluorescence Detector ◽

X Ray

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The fluorimetric determination of cerium and terbium

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19890616 ◽

1989 ◽

Vol 54 (3) ◽

pp. 616-621 ◽

Cited By ~ 3

Author(s):

Záviš Holzbecher

Keyword(s):

Rare Earth ◽

Detection Limit ◽

Rare Earth Elements ◽

Fluorimetric Determination ◽

Fluorescence Maximum ◽

Relative Standard ◽

And Shifts ◽

Hcl Medium ◽

Fold Excess

It has been found that phosphoric acid decreases the first excitation maximum of Ce(III) at 256 nm, increases the second excitation maximum at 297 nm and shifts the fluorescence maximum from 350 to 346 nm. Under optimum conditions, with λexc = 297 nm and λem = 346 nm, Ce(III) can be determined fluorimetrically with a detection limit of 1.2 ng ml-1 in 12M-H3PO4 medium. No interference was observed from a 20-200 fold excess of HCl, H2SO4, Na, K, NH4+, Al and the rare earth elements. HNO3 interferes and Ce(IV) and Fe(III) interfere strongly. It follows from the stereofluorograms of Ce and Tb that the spectra of the two elements are practically independent. The detection limit for Tb(III) in 0.02-2.5M-H2SO4 medium for λexc = 222 nm and λem = 494 nm is 33 ng ml-1. No interference was observed from a 5-20 fold excess of Al3+ and the other rare earth elements. The determination is slightly less sensitive in H3PO4 or HCl medium. The relative standard deviation of the measurement for 10 ng ml-1 Ce(III) or 50 ng ml-1 Tb(III) is about 3%.

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