Improving the assessment and subsequent remediation of sites contaminated with aromatic amines requires differentiating between reversible and irreversible sorption processes and quantifying the controlling parameters. The interaction of anilineandα-naphthylamine with five surface soils from CaCl{sub}2 electrolyte solutions was studied for a 2 month equilibration period using a batch equilibration method. Soils varied in pH (4.4-7.4), cation exchange capacity (CEC, 4.4-36.2 cmol{sub}c/kg), andorganic carbon content (OC, 0.4-5). Reversible sorption processes reached equilibrium within the first day of equilibration for all soil-solute combinations while irreversible binding and transformation proceeded for much longer times. After 1 day,increases over time in the ratio of reversibly sorbed concentrations to solution concentrations were shown to primarily result from nonlinear sorption coupled to decreasing aqueous solute concentrations from irreversible binding/transformation. Dimerformation hypothesized to be mineral catalyzed was confirmed with GC/MS and UVvis detection forα-naphthylamine, but was not observed for aniline. Fast reversible sorption processes reduced aromatic amine concentrations in solution and retardedirreversible reactions indicating processes occur in parallel.
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