Heavy metal, surfactant, ligand interactions in soil remediation

Abstract

In this study, heavy metal-surfactant-ligand interactions and the effects of anionic and nonionic surfactants alone, two ligands alone, and combinations of these surfactants and ligands in the removal of heavy metals from soil were investigated. Soil was taken from Tekirdağ region. 2 g soil samples were polluted with cadmium and lead at different concentration values and V/m = 20 and 40 mL g-1 ratios. The soil samples were polluted with 4, 6, and 8 mg L-1cadmium solutions for 48 hours, the other samples were polluted with 2, 4, 6, 8, and 12 mg L-1 lead solutions for 72 hours and 16 and 20 mg L-1 lead solution for 96 hours which were determined as the equilibrium time of the interaction between the pollutant ions and soil. The study showed the results from a number of washing treatments using two surfactants, anionic SDS and nonionic Triton X-100 and two chelating agents, iodide and citric acid and the combination of the surfactant-ligand systems aiming at the remediation of artificially heavy metal-contaminated soil. The soil samples were shaken for 25 hours on a shaker at a temperature of 25±2°C and the supernatant fraction was determined by Atomic Absorption Spectroscopy (AAS) and Differential Pulse Anodic Stripping Voltammetry (DPASV). The most efficient Cd desorption values were obtained using combination of Triton X100-citric acid up to 100 percent, SDS-iodide up to 95 percent, and Triton X100-iodide almost 85 percent. In the removal of lead studies, the best results were obtained with the combination of SDS-iodide and Triton X100-iodide systems which were up to 80 percent with SDS-iodide, 90 percent with Triton X100-iodide.