Role of humic substances in the partitioning and transport of copper(II) in ground-water aquifers. Final report
Partitioning and transport of Cu(II) in the presence of natural organic matter (NOM) were investigated in both batch and continuous-flow column experiments. Experimental variables included: pH (6.2 and 7.5), background electrolyte and different NOM sources and isolation procedures. Groundwater NOM was studied in its original groundwater matrix and as isolated humic substances. Porous media was either SiO2 or a mixture of SiO2 and Al2O3. Cu(II) affinity varied for different sources of organic matter; strongest binding was to isolated groundwater humates. This may be due to the presence of competing cations (Mg(2+) and Ca(2+)) in experiments using NOM in the groundwater matrix. Results of column experiments at pH 6.2 suggest that mobile humates facilitate the transport of Cu(II) by lowering the free Cu(II) concentration. Mineral-bound humics retarded the transport of Cu(II) by increasing the concentration of immobile binding sites and by binding considerably more Cu(II) per mass carbon than aqueous humics. Column experiments at pH 7.5 show NOM greatly facilitated transport of Cu(II) compared to pH 6.2. The predicted steady state partitioning of Cu(II) to the immobile phase was predicted from Langmuir isotherms while the transport of Cu(II) was predicted by applying these isotherms to the equilibrium one-dimensional transport model.
- Research Organization:
- Arizona Univ., Tucson, AZ (United States). Dept. of Hydrology and Water Resources
- OSTI ID:
- 5823663
- Report Number(s):
- PB-92-118132/XAB; CNN: DI-14-08-0001-G1635
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
ADSORPTION
ALKALINE EARTH METAL COMPOUNDS
AQUIFERS
CALCIUM COMPOUNDS
CATIONS
CHARGED PARTICLES
COPPER
ELECTROLYTES
ELEMENTS
ENVIRONMENTAL TRANSPORT
GROUND WATER
HYDROGEN COMPOUNDS
IONS
MAGNESIUM COMPOUNDS
MASS TRANSFER
MATHEMATICAL MODELS
MATTER
METALS
MINERALS
ORGANIC MATTER
OXYGEN COMPOUNDS
POLLUTION
SORPTION
TRANSITION ELEMENTS
WATER
WATER POLLUTION