On the evaluation of the intrinsic stability of indium-nanoparticulate organic matter complexes

Proper evaluation of the intrinsic stability metal complexes with humic nanoparticles calls for a robust representation particulate electrostatic features. Addressing here case trivalent association humics which significant contribution is expected, we report interpretative approach as an alternative to conventional but approximative Donnan model applied in popular speciation codes. The chemical binding affinity Indium addressed from equilibrium electroanalytical measurements (Absence Gradient and Nernstian Equilibrium Stripping) NaClO4 electrolyte (10–100 mM, pH4) at different metal-to-humics concentration ratios. was evaluated using Poisson-Boltzmann based-approach where key descriptors are involved. electrochemical results interpreted light so identified non-specific indium evidences dramatic impact electrostatics on complexation by humics, e.g. 10 mM intraparticulate Boltzmann accumulation factor that ca. 5 times larger than reported cadmium highly-charged fulvics complexants. A successful comparison between theory experiments consistently achieved over tested concentrations only adjustment radius spherical volume. analysis reveals necessity consider full equilibration charged its counterion atmosphere.