3 resultados para TRANSPORT SYSTEMS
em SAPIENTIA - Universidade do Algarve - Portugal
Resumo:
Dissertação de Mestrado, Ciências Económicas e Empresariais, Unidade de Economia e Administração, Universidade do Algarve, 1996
Resumo:
Tese dout., Química, Universidade do Algarve, 2005
Resumo:
A lability criterion is developed for dynamic metal binding by colloidal ligands with convective diffusion as the dominant mode of mass transport. Scanned stripping chronopotentiometric measurements of Pb(II) and Cd(II) binding by carboxylated latex core-shell particles were in good agreement with the predicted values. The dynamic features of metal ion binding by these particles illustrate that the conventional approach of assuming a smeared-out homogeneous ligand distribution overestimates the lability of a colloidal ligand system. Due to the nature of the spatial distribution of the binding sites, the change in lability of a metal species with changing ligand concentration depends on whether the ligand concentration is varied via manipulation of the pH (degree of protonation) or via the particle concentration. In the former case the local ligand density varies, whereas in the latter case it is constant. This feature provides a useful diagnostic tool for the presence of geometrically constrained binding sites.