A fundamental study on the remediation of contaminated soil with heavy metals based on electrokinetic and magnetic properties

The fundamental issues concerning the remediation of contaminated soils with heavy metals using electrokinetic and magnetic properties of soils are discussed in this study. Firstly, the influences of magnetic force or the Lorentz force on the behavior of heavy metal ions was investigated. It was clarified that this influence on the movement of lead ions in soil is relatively small. Secondly, the ferrite method used for the disposal of effluents containing heavy metals was applied to the contaminated soil. It is known that ferrite, which is a compound oxide with iron and heavy metals, has ferromagnetism and its solubility is very low. From the test results, it was confirmed that the insoluble property of the ferritization-treated soil or the compound hydroxide for Pb-contaminated soil is much higher over a wide range of pH levels. It was also observed that the insoluble property of lead increases gradually with the iron content. Furthermore, the magnetic property of the ferritization-treated soil was investigated. Since the ferritization-treated soil exhibits ferromagnetism, magnetic separation using a superconducting magnet was attempted. Although ferrite and clay particles could not be separated adequately, it is suggested that the ferrite method may be one of the techniques for the remediation of contaminated soil with heavy metals.