Electrode Measurement of Redox Potential in Anaerobic Ferric/Ferrous Chloride Systems

摘要

The behavior of two inert redox electrodes (Pt and wax-impregnated graphite) was investigated in anaerobic ferrous and ferric chloride solutions in order to establish if these electrodes respond to the Fe(3+)/Fe(2+) couple in a Nernstian manner. A new method for determining dissolved ferric iron at any point in time was used which permitted the calculation of Eh values that are independent of variations in the solubility of ferric oxyhydroxides. This method is applicable to simple iron solution at pH levels of 4 or less. In solutions of ionic strength greater than 0.005M, both electrodes yielded measured potentials that correspond to the value calculated by the Nernst equation. In solutions of ionic strength less than 0.005M, electrode response became non-Nernstian behavior. (Copyright (c) 1989 Elsevier Science Publishers B.V.)