Production of Permanganate Ion by Sodium Hypochlorite Treatment to Remove Soil Organic Matter

Abstract

Abstract The pink color characteristically produced during NaOCl treatment of soil to destroy organic matter was studied. Colored extracts were analyzed for Mn content and Redox potential. A spectrophotometer scan of one extract was compared with a scan of KMnO 4 solution, and the extract color was shown to be caused by the MnO 4 ‐ ion. The time of appearance and the intensity of the color were related to the organic matter contents of the samples. The source of the Mn was probably Mn(II) released from organic matter during oxidation. The MnO 4 ‐ color appeared when the Redox potential shifted to about + 1.2 V, and was thus a reliable indicator of the approximate end of the organic matter oxidation process.