Hexavalent chromium detoxification by three species of aquatic macrophytes

F.R. ESPINOZA QUIÑOES; N. MARTIN; G. STUTZ; G. TIRAO; A.N. MÓDENES; S.M. PALACIO; M.A. RIZZUTTO; F.G. SILVA JR

LNLS, Campinas Brasil

Congreso; Activity Report LNLS 2007; 2008

LNLS

Metal phytoextraction depends on metal-accumulating plants to absorb, transport and concentrate polluting heavy metals from the soil into the plant. Among the great variety of plants, macrophytes are known to assimilate pollutants by surface adsorption and/or absorption and incorporate directly into their tissues. Nowadays, the X-ray spectroscopy has become the most powerful tools in modern physics and chemistry in order to obtain information about the chemical and physical properties of the sample. In this work special attention is given to X-ray emission from 3d-transition metal compound or plant-accumulated metal. The 3d transition metal spectra are often dominated by chemical environment which is observed when Kb transitions are considered in study. The Cr-Kb satellite lines are predominately governed by the contribution by the transitions from valence band to core electronic states which their energies may be strongly dependent on the oxidation state. The emission energy of the Cr-Kb” can also be used as a fingerprint of the presence of chemical bonds in the sample. The aim of present work was to investigate the detoxication of hexavalent chromium by plant rootbased adsorption using a hydroponic solution supplied with non-toxic chromium doses as growth media. Floating aquatic macrophytes Salvinia auriculata, Pistia stratiotes and Eicchornia crassipes were studied as living plant-based chromium reduction using a high-resolution X-ray fluorescence technique in order to indentify chemical ligands and Cr oxidation state into the plant tissue.