Adsorption/desorption in a system consisting of humic acid, heavy metals, and clay minerals
Metal adsorption/desorption in a system consisting of humic acid, metal ions, and clay minerals is described. Montmorillonite and purified humic acid were selected as prototype materials for this study. At a constant ionic strength, the amount of humic acid adsorbed on montmorillonite decreases when pH is increased. A slight increase in humic acid adsorption on montmorillonite is observed when there are bivalent metals present in the system. The metal adsorption on montmorillonite does not correlate to the amount of humic acid adsorbed on montmorillonite. Montmorillonite with preadsorbed humic acid does not show a significant change in the capacity of adsorbed metal ions. An increase in the ionic strength at a pH of 6.5 results in an increase in the adsorption of lead on montmorillonite in the presence of humic acid, while at a lower pH, the increase in ionic strength results in a decrease in metal adsorption. The bridging of bivalent metal ions between montmorillonite and humic acid is proposed as the dominant adsorption mechanism.
- Research Organization:
- Tulane Univ., New Orleans, LA (US)
- OSTI ID:
- 20000026
- Journal Information:
- Journal of Colloid and Interface Science, Journal Name: Journal of Colloid and Interface Science Journal Issue: 1 Vol. 218; ISSN 0021-9797; ISSN JCISA5
- Country of Publication:
- United States
- Language:
- English
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