Initial sorption of aromatic amines to surface soils
- Purdue Univ., West Lafayette, IN (United States)
Sorption of aniline, {alpha}-naphthylamine, and benzidine to three silty clay loams was measured from CaCl{sub 2} electrolyte solutions in single and binary solute systems after a 1-d residence time. Soils varied in pH cation-exchange capacity and organic carbon content. Plots of sorbed amine concentrations versus aqueous amine concentrations exhibited nonlinearity in the concentration range investigated. Sorption increased with decreasing soil-solution pH for all solutes. Decreases in sorption with increasing CaCl{sub 2} concentrations were greatest at low pH. In binary solute experiments, {alpha}-naphthylamine depressed the sorption of aniline and this depression increased with decreasing pH. Normalizing sorption to the cation-exchange capacity of the protonated species compensated for most of the differences observed between soils at different pH values suggesting that cation exchange is the primary process occurring during initial contact times. In selected experiments, sorbed aromatic amines were extracted from soils with different solvents after a 1-d incubation. At low initial concentrations only a few percent of each amine was extractable; whereas 85% to 98% was recoverable at higher initial concentrations. Although initial sorption appears to be to cation-exchange sites, the inability to recover all of the sorbed amine suggests early covalent bond formation on highly reactive sites and/or sorption to high-energy sites on clays or other soil constitutents.
- Sponsoring Organization:
- Environmental Protection Agency, Washington, DC (United States)
- OSTI ID:
- 538155
- Journal Information:
- Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 8 Vol. 16; ISSN ETOCDK; ISSN 0730-7268
- Country of Publication:
- United States
- Language:
- English
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