Département de chimie moléculaire

The complexing ability of thin poly(3-pyrrol-1-ylpropyl)malonic acid films coated onto glassy C disk electrode surfaces was evaluated towards Pb(II) and Cu(II) ions, using the chem. preconcn.-anodic stripping method. The affinity of these metal cations for the complexing film modified electrodes and their maximal surface coverage rate could be evaluated from a Langmuir isotherm model coupled to the chem. preconcn.-anodic stripping technique. Isothermal studies conducted between 293 and 308 K allowed to est. enthalpy and entropy variations assocd. to the metal sorption, which expectedly proved to fit chemisorption processes. As judged from the estd. binding consts., Pb(II) ions turned out to present a higher affinity for the functionalized surface than the smaller Cu(II) species. The mobilization of a higher no. of malonic acid units per metal cation upon complexation of Pb(II), as compared to Cu(II), is however believed to account for the estd. lower Pb(II) surface coverage. The combination of the Langmuir isotherm model to the chem. preconcn.-anodic stripping technique is thus revealed to be an efficient method to characterize the complexing ability of complexing film electrode surface. [on SciFinder(R)]