Use of Surfactants in Removal of Zinc, Lead and Cadmium from Contaminated Soils

Abstract

This thesis was conducted to study the effects of surfactants and chelating agents on the removal of zinc, lead and cadmium from contaminated soils. These metals are commonly found among most Superfund sites and are considered toxins, according to the Environmental Protection Agency. This report is organized into several sections. The introduction describes the problems with having heavy metals present in high concentrations in the soil. The literature review discusses other research, first describing why removal is so difficult and then what must be done in order to remove metals from the soil. Previous research involving the use of surfactants and chelating agents is also evaluated. The next section describes the preliminary tests that were run in order to establish optimum test procedures and the setup of the experiments. In the results and discussion section the removal efficiencies of both surfactant and combinations of a chelating agent, citric acid, are be presented. This is followed by a sequential extraction procedure that shows the partitioning of each of the three metals into four soil fractions. Hypotheses are then presented as to why metals were or were not removed. These results are then compared to similar studies performed by other researchers, to put this project into perspective relative to the state of the art of removing metals from soils using surfactants and/or chelating agents.