Adsorption of copper ions by a mixture by oligogalacturonides for use in bioremediation

Abstract

The mixture of oligogalacturonides (Ogal) from citric peel. This product presents a degree of polymerization
between 7 and 16. Each galacturonic residue has a terminal carboxyl group allowing the formation of complex with heavy
metals. In this work the stability constants of the formed complexes between the mixture of Ogal and the ion copper (II)
were determined by potentiometric titration turning out of 18,5 ± 0,2 and 3,1 ± 0,2 respectively, being evidenced that the
studied complexes are stable. The formed complexes were characterized in solid phase by IR- spectroscopy and thermal
analysis, determining the main affectations in the unctional groups product of the ionization and it is appreciated that the
complexes are less stable thermally than the departure Ogal. On the other hand were carried out rehearsals analyzing the
possibility, that the mixture of oligogalacturonides could protect tomato seedlings variety Amalia growing with toxic
levels of metal, being evaluated the fresh and dry mass foliate and radical as well as the longitude of the root, observed a
bigger radical growth and a decrease of the height of the plants tried with this product, effects that counteract the effect
of the toxicity for Cu2+. The content of metals was determined in these organs by atomic adsorption, existing a change in
the pattern of accumulation of the metals in these organs.