Intraparticulate metal speciation analysis of soft complexing nanoparticles. The intrinsic chemical heterogeneity of metal-humic acid complexes

Raewyn M. Town*, Herman P. van Leeuwen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Scopus)

Abstract

The counterion condensation-Donnan (CCD) model for the electrostatic features of soft, charged nanoparticles (NPs) is applied to the determination of the intrinsic stability constants, K̄int, for inner-sphere Cd(II) and Cu(II) complexes with humic acid NPs. The novel CCD model accounts for the strong ion condensation potential for higher valency counterions within the intraparticulate double layer zone of the soft NP. The approach offers new insights into the intrinsic heterogeneity of the HA complexes, as revealed by the intraparticulate speciation as a function of the true degree of inner-sphere complexation, θM. The ensuing intrinsic heterogeneity parameters, Γ, for CdHA and CuHA complexes are in very good agreement with those obtained from dynamic electrochemical stripping chronopotentiometric measurements. The overall intraparticulate metal ion speciation is found to depend on θM: at low θM the strong inner-sphere complexes predominate whereas at higher θM values, electrically condensed M may be an equally significant or even larger fraction of the particle-associated M. (Graph Presented).

Original languageEnglish
Pages (from-to)8637-8644
JournalThe Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment, & General Theory
Volume120
Issue number43
DOIs
Publication statusPublished - 2016

Fingerprint Dive into the research topics of 'Intraparticulate metal speciation analysis of soft complexing nanoparticles. The intrinsic chemical heterogeneity of metal-humic acid complexes'. Together they form a unique fingerprint.

Cite this