Bioconcentration of Rare Earth Elements lanthanum, gadolinium and yttrium in algae (Chlorella Vulgarize Beijerinck): Influence of chemical species

In this paper, the species of Rare Earth Elements (La, Gd and Y) complexed with organic ligands EDTA (ethylenediamine tetraacetic), NTA (nitrilotriacetic acid) and Cit (citrate) were calculated in the test medium by MINTEQA — A program to calculate aqueous geochemical equilibrium. The influence of the species on the bioconcentration (kinetics and thermodynamics) processes of REEs by algae (Chlorella Vulgarize Beijerinck) were also studied. The results show that the bioconcentration processes of REEs by algae were highly dependent on chemical species. Adding organic ligands which can form RE-Organic species complex led to a great reduction of the REEs bioconcentration in algae. The order of BCFs from high to low is RE3+ > RE-Cit > RE-NTA > RE-EDTA complex. The potential mechanism of bioconcentration may be the coordination reactions of REEs ions with the active sites on algae surface followed by the slow diffusion into the algae cell.