Silver Binding by Humic Acid as Determined by Equilibrium Ion-Exchange and Dialysis
| Autor: | Zhongzhi Chen, Claude Fortin, Peter G. C. Campbell |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
chemistry.chemical_classification
Binding Sites Silver Ion exchange Chemistry media_common.quotation_subject Inorganic chemistry Metal Speciation visual_art Dissolved organic carbon visual_art.visual_art_medium Humic acid Equilibrium dialysis Ion Exchange Resins Physical and Theoretical Chemistry Binding site Ion-exchange resin Dialysis Humic Substances media_common |
| Zdroj: | The Journal of Physical Chemistry A. 116:6532-6539 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/jp212403r |
| Popis: | One of the major challenges in environmental analytical chemistry is to develop methods for determining metal speciation in natural waters that contain low metal concentrations and dissolved organic matter (DOM). Because of its complex heterogeneous nature, metal binding to DOM cannot be predicted accurately using equilibrium models. Two independent speciation methods, the equilibrium ion-exchange technique (IET) and equilibrium dialysis (EqD), were used to determine silver binding by standard Suwannee River humic acid. Both approaches gave very similar results, although for a given silver loading, the concentration of free silver obtained by IET was somewhat higher than that determined by EqD. Our results suggest that any high-affinity binding sites present within the humic acid are likely saturated at [Ag(T)]10(-9) M. This comparison of free metal ion concentrations with two independent methods provides useful speciation information in the absence of reliable complexation constants for the reaction of silver with humic acid. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|