Acid/base, copper binding, and Cu2+/H+ exchange properties of a soil humicacid, an experimental and modeling study

Citation
Ap. Robertson et Jo. Leckie, Acid/base, copper binding, and Cu2+/H+ exchange properties of a soil humicacid, an experimental and modeling study, ENV SCI TEC, 33(5), 1999, pp. 786-795
Citations number
42
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
Journal title
ENVIRONMENTAL SCIENCE & TECHNOLOGY
ISSN journal
0013936X → ACNP
Volume
33
Issue
5
Year of publication
1999
Pages
786 - 795
Database
ISI
SICI code
0013-936X(19990301)33:5<786:ACBACE>2.0.ZU;2-#
Abstract
Acid/base, copper binding and proton exchange properties of a soil humic ac id were studied over a range of pHs and ionic strengths. Results indicate t hat multiple classes of copper binding sites exist. A number of model formu lations were used to simulate the data; none were able to reasonably match all aspects of the observed behavior. Model results and analyses suggest th at successful replication of humic behavior over a wide range of conditions requires a model formulation which incorporates electrostatic effects for a variable geometry entity, multiple site classes, and probably both uni an d multi dentate complexation. Additionally site heterogeneity estimates fro m acid/base titration data are not likely to reasonably assess the presence of low concentration, high (metal) affinity sites that can be relevant in the study of trace metal complexation.