Estimation of Iron Content in Water Using Conductometric Method

Abstract

Iron content is one of the important parameters of water quality. Permanganometric method is a very common technique to estimate Fe2+ ion. However, this technique fails to estimate Fe3+ ion but water sample contains both Fe2+ and Fe3+ ions. Colourimetric method is popular to estimate iron content in a given water sample. However, it has some limitations e.g., the method is sensitive to pH and temperature. Furthermore, the method is applicable to a limited concentration range. The present work proposed a novel technique, conductometric method, to estimate iron content in a given water sample. The method is based on change in ionic conductance of Fe2+ ion during formation of iron-phenanthroline complex. A calibration curve is obtained while plotting change in ionic conductance values against known concentrations of Fe2+ ion. Using this calibration curve unknown concentration of Fe2+ ion in a given sample water can be determined by measuring corresponding change in ionic conductance of Fe2+ ion in presence of 1,10 phenanthroline. This novel technique is applicable in a wide concentration range. In the present work two unknown samples with concentrations, 0.084 (N/100) and 0.20 (N/100), are used. Using the calibration curves the corresponding concentrations are found to be 0.085 (N/100) and 0.19 (N/100) respectively, indicating that the experimental results are very close to the actual values. The other advantages of this method are: (a) it is simple and easy to perform anywhere, (b) it is cost-effective, (c) the accuracy of the method does not depend on either  pH or temperature of experiment.