Copper binding by dissolved organic matter. I. Suwannee River fulvic acid equilibria

Journal Article · Fri Jan 01 00:00:00 EST 1988 · Geochim. Cosmochim. Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(88)90066-X· OSTI ID:7222736

Cabaniss, S E; Shuman, M S

A cupric ion-selective electrode measured free Cu in solutions of Suwannee River fulvic acid (FA) in a series of 30 titrations carried out both at variable and at constant (5.14, 7.00, 8.44) pH. Total Cu varied 0.1-100 ..mu..m, dissolved organic carbon (DOC) 1-10 mg C/l, Ca and Mg 0-10 mM, and ionic strength 0.005-0.1. Copper complexation by FA is first order in DOC for 1-10 mg C/liter, and variable-order in pH. Increasing Ca/sup + +/ or Mg/sup + +/ from 0 to 10 mM slightly increases Cu/sup + +/ activity, while increasing ionic strength from 0.005 to 0.1 significantly increases Cu/sup + +/ activity. An empirical N-site model was calibrated using a pooled set of six titrations with varying pH and DOC. Five binding components of varying proton dependence predict Cu binding by FA over a range of pH, DOC and total Cu in two verification tests of the model parameters. Parameters in this and other models tested are only empirical constructs.

• Research Organization: Univ. of North Carolina, Chapel Hill (USA)
• OSTI ID: 7222736
• Journal Information: Geochim. Cosmochim. Acta; (United States), Vol. 52:1
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
FULVIC ACIDS
CHEMICAL COMPOSITION
GEOCHEMISTRY
MOLECULAR MODELS
STOICHIOMETRY
CALCIUM IONS
CARBON IONS
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
COPPER IONS
EQUILIBRIUM
MAGNESIUM IONS
PH VALUE
RIVERS
WATER CHEMISTRY
CHARGED PARTICLES
CHEMISTRY
IONS
MATHEMATICAL MODELS
ORGANIC ACIDS
ORGANIC COMPOUNDS
STREAMS
SURFACE WATERS
580400* - Geochemistry- (-1989)