LAUSR

The removal of heavy metals from contaminated soil/water by biosurfactants depends on the ability of biosurfactant to form complexes with metals. The interaction of quillaja saponin, a nonionic natural biosurfactant, with heavy metal ions, viz. chromium(VI) and lead(II), has been studied spectrophotometrically and conductometrically in order to obtain detailed information for the saponin–metal complexes. Both the methods indicate complex formation between saponin and metal ions. Critical micelle concentration of saponin in the absence and presence of metal ions obtained by both the methods was in good agreement. The thermodynamic parameters, viz. free energy, enthalpy and entropy change, for micellization have been determined.