Effect of Humic Substances and Their Precusors on Removal of Hexavalent Chromium in Soil by Electroremediation.

概要

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The influences of humic substances and their precursors, tannic acids and gallic acids, on the removal of hexavalent chromium from soil by electroremediation were investigated. For this purpose, a small simulator consisting of one migrating column and two chambers for the electrodes was prepared. Twenty voltages were applied between the electrodes at the both ends of the migrating column filled with clay containing hexavalent chromium as a model of polluted soil. In the absence of humic substances, most of hexavalent chromium moved to the anodic chamber as dichromate ion by electromigration. In the presence of humic substances, however, migration of some chromium in the direction of the catholic chamber was observed. Furthermore, the presence of tannic acid or gallic acid, which are referred to as precursors of humic acid, reduced most of hexavalent chromium to trivalent chromium, which was migrated to catholic chamber. The process seems to be very important for removing hexavalent chromium from clayly soil, because chromium into soil can be removed as nontoxic trivalent chromium and therefore the diffusion of hexavalent chromium can be suppressed. At least 90% of hexavalent chromium could be removed under certain condition.
日本環境化学会の論文