Absorption of Mercuric Cation by Tannins in Agricultural Residues1
- A. C. Waiss,
- M. E. Wiley,
- J. A. Kuhnle,
- A. L. Potter and
- R. M. McCready2
Two common environmental pollutants are agricultural residues (skins, pits, husks, tannin bark, grape pomace) and waste streams of water containing only traces of heavy metals (such as mercury at 10 or more ppb) from mining or manufacturing operations. Agricultural residues contain tannins, polyphenolic substances, pectin, and other polymers—all with chemically reactive groups that can chelate, reduce, oxidize, demonstrate ion exchange properties, and aid in removing traces of heavy metals from dilute waste water streams at low cost.
Finely ground and water-washed agricultural residues were slurried in water and packed into columns for absorption tests with heavy metals. Solutions of known concentrations of heavy metals were passed through the packed columns which were then eluted with water or with alkaline or acidic solutions. The fractions and the column absorbents were then analyzed by standard atomic absorption methods.
The nature of the physical and chemical forces that are effective in metal absorption from agricultural residues is not clear.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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