REMEDIATION OF CHROMIUM CONTAMINATED WATERS BY D-GALACTURONIC ACID POLYMERS. PRELIMINARY STUDIES

SEBASTIAN BELLÚ; JUAN CARLOS GONZÁLEZ; MARÍA JOSE CERUTI; NADIA MAMANA; SILVIA GARCÍA; LUCIANO BRAMBILLA; SANDRA SIGNORELLA; LUIS F. SALA

BIOCELL

INST HISTOL EMBRIOL-CONICET

Lugar: Mendoza; Año: 2005 vol. 29 p. 115 - 115

0327-9545

Cr(VI) is known to be a carcinogenic and mutagenic agent; and Cr(III), although an essential micronutrient, can be oxidized to Cr(VI) by hydrogen peroxide under physiological conditions. There is increasing interest to develop new methods for the removal of total Cr from industrial waters using cheap substances able to reduce Cr(VI) to Cr(III) and to retain Cr(III) into a solid matrix. With this in mind, the ability of D-Polygalacturonic acid (D-pGal) to act as reductant of Cr(VI) and trapper of Cr(III) was evaluated. The redox reaction was found to be: D-pGal + Cr(VI) = DpGal(oxidized) + Cr(III) + formic acid, and the reaction products were detected and quantified by HPLC, using an ion exchange column. Spectrophotometric measurements of a reaction mixture at 350 nm, in heterogeneous phase, at pH = 1.0 and 60 ºC, showed that 1 g of D-pGal was able to reduce 0.18 g of potassium dichromate in 9 h. At the same time, the absorbance intensity at 570 nm did not show the expected increment, pointing out that Cr(III) remains retained into the solid matrix of D-pGal. Additional studies on D-pGal and Cr(III) mixtures at pH 1 and 12, in heterogeneous phase, showed that D-pGal was capable to bind Cr(III). These results indicate that the D-galacturonic acid polymers are able to reduce and retain chromium into their matrix.