An-Najah Staff

Heavy metals are persistent pollutants in the environment. Problems associated with the cleanup of sites contaminated by metals have demonstrated the need to develop remediation technologies that are feasible, quick, and effective in a wide range of physical settings. Experiments were conducted to investigate the efficiency of surfactants and ligands on cleaning artificially contaminated red, sandy and white chalk soil samples with heavy metals e.g. (Cd (II), Cu (II), Pb (II) and Zn (II)). Before contamination, soils were characterized to determine particle size, pH, organic matter content and heavy metal contents. The results of experimental sorption data fitted very well the Freundlich isotherm model and first order kinetics model.In this study we have investigated the adsorption of Cd (II), Cu (II), Pb (II) and Zn (II) onto each soil in single and multi-element systems as a function of soil and heavy metal concentrations. The best pH for adsorption of Cu2+ on red soil was found to be 4.0.Adsorption of metals on soil increased in the order Cu > Pb > Zn Cd.This trend might be related to the increase in the electronegativity of the metalion. Surfactants are efficient soil remediation agents for heavy metals.Various concentrations of four different surfactants Triton; X-100, SDS, Tergitol and Tween 80 were used as washing solution for remediation of contaminated soils. Triton X-100 (0.1 M) was the best surfactant to desorb copper from red soil. Tween 80 was the best surfactant to desorb copper from sandy and white chalk soils. Recently, ligands were enhancing surfactants to desorb heavy metals from contaminated soils. Surfactants in combination with ligands were tested as washing agents for contaminated soils. Different concentrations of three different ligands (I- , SCN- and EDTA) along with nonionic surfactant, Triton X-100 were applied as soil washing agents to desorb copper from artificially contaminated soils. Triton X-100 with 0.1 M EDTA showed a higher capacity to desorb copper than did with 0.4 M SCN‑ or 0.4 M I-.The increase of ligand concentration was a critical factor for increasing leaching capacity. Without the presence of a ligand, the surfactant alone was not able to desorb copper effectively from soil.