Copper binding by goethite as a function of pH and ionic strength - experimental and surface complexation modelling results

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:370471

Robertson, A P; Leckie, J O ^[1]

---

1. Stanford Univ., CA (United States)

Goethite acid/base and copper partitioning properties were studied as a function of ionic strength, pH and copper loading. The data were fit to surface complexation models using FITEQL. The Triple layer model(TLM) and a variant replicated the acid base properties well; Diffuse layer model(DLM) fits were poor. Good fits of the copper data required at least 2 classes of copper binding sites. With 2 or 3 classes of sites each model gave a good fit for at least one inner sphere complex stoichiometry or combination of stoichiometries. Outer sphere complexes gave poor fits in all cases. No {open_quotes}best{close_quotes} copper binding fit could be determined. The modelling results suggest that there are relatively subtle differences in the pH and ionic strength dependencies of the various good fit stoichiometries. However, in general, obtaining the data necessary to distinguish among these differences from metal partitioning experiments will at the least require careful, precise experimental design and execution.

• OSTI ID: 370471
• Report Number(s): CONF-960376--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
54 ENVIRONMENTAL SCIENCES
ADSORPTION
BINDING ENERGY
COPPER
ENVIRONMENTAL TRANSPORT
GOETHITE
MATHEMATICAL MODELS
OXIDE MINERALS
PH VALUE
STOICHIOMETRY
SURFACE PROPERTIES