Combined Utilization of Different Inorganic Binders for Solidification/Stabilization of Contaminated Soil: An Overview

One of the most serious environmental issues is the widespread contamination of soils with heavy metals due to increasing industrial activities and other processes such as mining. Various techniques are available for the remediation of contaminated soil. One of the most effective and cost-efficient methods is Solidification/Stabilization. In the Solidification/Stabilization (S/S) technique, cementitious binders are mixed with heavy metal contaminated soil in order to transform the soil into a solid material with low leachability of contaminants and enhance the mechanical strength of the contaminated soil. Portland cement is the most popular binder used in the S/S technique, but on the other hand, it is also drawing criticism due to the negative effects its manufacture has on the environment. Various other binders such as Ground Granulated Blast-furnace Slag, lime, waste phosphorus slag, geopolymer, red mud, and combinations of different materials are used as an alternative for Portland cement. The current study critically examines the performance of various inorganic material combinations used as binders for S/S of contaminated soil and provides a comprehensive analysis of the mechanisms responsible for the immobilization of contaminants in the soil as well as the factors that influence the process. Hence, this paper seeks to fill that gap in the literature by providing useful insight into some of the works done by previous researchers on the combination of binders to treat contaminated soils.