Metal complexation with surface-active Kemp's triacid

Metal-complexation agents are extensively used in current environmental rem ediation practices for the removal of adsorbed heavy metals/radionuclides f rom various solid matrices via chelation and solubilization, or for the sel ective reclamation of desired species from a solution mixture. These comple xing agents are mostly anions. Some of the complexing species may also poss ess surface-active properties, which make them particularly suitable for ap plications involving decontamination of mixed organic and inorganic wastes. This study illustrates one such surface-active molecule, Kemp's triacid (C hemical and Engineering News, News story on ACS Award to D.S. Kemp, Jan. 27 , 1997), which functions equally well as a complexing agent for heavy metal s, namely copper and lead. The triacid has been found to complex lead most selectively in the presence of other metal ions. The metal-complexation rea ctions were dictated by the pH of the bulk solution, as demonstrated by the UV-visible and Infrared spectroscopic data. Complexation reactions at the oil-water interface resulted in the modification of surface charge on the o il-in-water emulsion droplets. Electrophoretic mobility and interfacial ten sion measurements supported these conclusions. This study is expected to ha ve far reaching implications in the use of surfactant-based systems (micell ar, oil-in-water microemulsion or macroemulsion systems) for future environ mental remediation purposes. (C) 1999 Elsevier Science B.V. All rights rese rved.