NEUTRALIZATION OF ACIDIFIED RIVER WATER USING AN ELECTROLYTIC CELL WITH THE POROUS ELECTRODE

Abstract

 Acidification of river water by an inflow of acidic spring had made it difficult to utilize the river water as domestic, industrial and irrigation waters. A large-scale neutralization work using a milk of lime has been conducted to improve water quality of the acidic river. The neutralization work must be continued to keep the improved river water quality. A novel electrochemical process for neutralization of the acidified river water was proposed in this study. The electrochemical experiments using the cell with the porous (molded activated carbon) electrode were carried out under the various operating conditions. In the continuous experiments using the acidified river water as feed solution, the solution in the cell was alkalified than a pH of 10 when the molded activated carbon was used as anode. The rate of pH rise was increased with the increment of the electric current and HRT (hydraulic retention time). On the other hand, in the continuous experiments using an alkaline solution, the solution in the cell was acidified than a pH of 4 when the molded activated carbon was used as cathode. The rate of pH drop was increased with the increase in applied current. In the control experiments using the stainless plate in place of the molded activated carbon, pH in the cell was slightly changed. From these results, it was considered that neutralization of the acidified river water could be attributable to the charge imbalance caused by the applied electrical field in which anions move toward the negatively charged porous anode. The electrochemical process proposed can be utilized for the neutralization of the acidified river water.