Chromium interaction with polyuronic compounds

SALA, L. F.; SIGNORELLA, S. R.; GONZÁLEZ, J. C.; BELLÚ, S. E.; GARCÍA, S. I.

Jerusalem, Israel

Conferencia; 38th INTERNATIONAL CONFERENCE ON COORDINATION CHEMISTRY; 2008

ICCC38

Chromium is usually encountered in the environment in (III) and (VI) oxidation states. It is released by efluent discharge from steelworks, chromium electroplating, leather tanning and chemical manufacturing. The interaction of Cr(VI) with natural substances might afford soluble species of Cr(V) of high stability that can be introduced in the ecological system and produce toxic effects. To avoid this, the presence of natural products which retain Cr(V) and reduce it to Cr(III) is desirable. Polyuronic compounds (polygalacturonic and pectic polysaccharides) are ideal substances to accomplish this purpose. Reaction of polyuronic compounds as well as oligomeric forms with Cr(VI) in acidic medium afforded Cr(V) complexes which were detected by EPR measurements. Cr(V) complexes were characterized and structural formul were proposed. At a same time solid Cr(III)-polysaccharide complexes were analyzed and the final conclusion is that polyuronic compounds are ideal for reducing Cr(VI) and trapping Cr(III) ions in a solid matrix.