Influence of Concentration of the Washing Solution and Freeze-Thaw Cycles on the Efficiency of the Washing Technology Using Freeze-Thaw and Ion Exchange

Abstract

It is difficult to wash the contaminated fine-grained soil because the contaminants are absorbed strongly into the soil particle surface. In order to remove the contaminants which are absorbed the fine-grained soil, the washing method which is applied the function of freeze-thaw and ion exchange was proposed. In this method, the washing solution is flowed the soil particle surface by the soil freezing, the washing solution which contains ion exchange substance removes the contaminants from the soil surface and the contaminants are drained at the time of the soil thawing.In this study, the natural potassium was used as the contaminants and the ammonium acetate solution was used as the washing solution. The purpose of this study is to clarify the effective removal condition for the natural potassium ions contained sample soil. In this paper, it was investigated that the influence of the concentration of the ammonium acetate solution, times of supplying ammonium acetate solution and freeze-thaw cycles.The test result revealed the following.(1) Both washing solution intake and contaminants drainage reduced in the case of the high concentration of the ammonium acetate while the content of potassium in the drainage increased. (2) Reduction of numbers of supplying ammonium acetate solution and increment of numbers of supplying water increased both washing solution intake and drainage then that drained the contaminants effectively.