Effects of polymeric charge variations on the proton‐metal ion equilibria of humic materials
Open Access
- 1 March 1977
- journal article
- research article
- Published by Wiley in Limnology and Oceanography
- Vol. 22 (2), 281-289
- https://doi.org/10.4319/lo.1977.22.2.0281
Abstract
Except for specific molecular weights, humic materials have many of the chemical and physical characteristics of enzymes. Thus modified equations from the biochemical literature can provide a theoretical description of proton-metal ion interactions on humic substances. For a given ionizable group type, the members of the group are chemically identical within experimental error, and the observed variations in dissociation of humic acid and bonding strength of metal ion as a function of pH are quantitatively related to the electrostatic interaction between the cationic species and the negatively charged humic polyion. This approach allows experimental determination of intrinsic constants for dissociation of acid and formation of metal ion, i.e. equilibrium constants which are independent of all electrostatic effects. The intrinsic constants obtained for a few humic materials are compared to those of possible monomeric units. In addition, the intrinsic constants have been coupled with other experimental parameters to predict the concentration of metal ion bound to humic materials as a function of pH.Keywords
This publication has 1 reference indexed in Scilit:
- Note on chelation and solubility of certain metals in sea water at different pH valuesNetherlands Journal of Sea Research, 1966