Separation of cadmium(II), mercury(II), bismuth(III) and antimony(III) from drinking and river waters by flotation

The presence of hazardous metal ions in the environment is a potential problem to water and soil quality due to their high toxcity to plant, animal and human life. Moreover, these metals cannot be destroyed chemically as organic pollutants. Therefore, this investigation aims to present flotation as a simple and quantitative technique for the separation of Cd(II), Hg(II), Bi(III) and Sb(III). It depends on the formation of metal iodide anion [ MI4]((n-4)-), the combination with Fe(II) tris(1,10-phenanthroline) reagent (I), and flotation of the resulting chemical associate with oleic acid surfactant (HOL). The parameters influencing the flotation process, namely solution pH, iodide, Fe(II) tris(1,10-phenanthroline) and surfactant concentrations, temperature and foreign ions were examined. Moreover, the procedure was successfully applied to recover Cd(II), Hg(II), Bi(III) and Sb(III) ions spiked to drinking and river water samples.