Determination of distribution coefficient of geomaterials and immobilizing agents

Abstract

The fate and transport of reactive contaminant(s) in geomaterials (i.e., soils and rocks) and efficacy of the immobilization–remediation methodology of the contaminated geomaterials is governed mainly by the sorption and desorption characteristics of these geomaterials and immobilizing agents. As such, establishment of these characteristics becomes mandatory. To achieve this, batch tests are usually conducted and a distribution coefficient is obtained from Freundlich, linear, and Langmuir isotherms. However, the relative efficiency of these isotherms needs to be ascertained for selection of the appropriate distribution coefficient for a contaminant geomaterial – immobilizing agent system. With this in mind, conventional batch tests were conducted on various geomaterials and immobilizing agents, to establish their sorption and desorption characteristics. However, it should be noted that batch tests do not represent the real-life contaminant geomaterial – immobilizing agent interaction, and are quite cumbersome and time-consuming. Under these circumstances, correlating sorption and desorption characteristics of these materials with the electrical conductivity of their solutions seems to be a potential alternative. Utility of this concept for modeling real-life contaminant geomaterial – immobilizing agent interaction has also been demonstrated very well in this study.