Redox properties of organic material present in ultrafiltrated water samples taken from the Paraíba do Sul river, Brazil

摘要

Previous studies indicated that free radicals control organic matter redox activities. In the present study, organic matter of an ultra-filtrated material collected from seven samples taken seasonally from the Paraiba do Sul River for two years were titrated with an oxidizer (I2) in an inert atmosphere. Standard formal potential values for the electrode MOOx, MORed ranged from 0.754 to 0.786 V at a 25 ?oC temperature. Organic matter oxidation capacity (COx) per carbon mass varied according to pH values, and changes in COx were related to rainfall and river flow intensities.