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Sorption of nonpolar organics on minerals and aquifer materials

Thesis/Dissertation ·
OSTI ID:6603409

The sorption of nonpolar organic chemicals on hydrous oxides, clay minerals, and subsurface aquifer materials was studied using the batch isotherm technique. Radiolabeled (/sup 14/C) trichloroethylene, orthodichlorobenzene, naphthalene, and 1-methylnaphthalene were sorbed on mineral sorbents, subsurface aquifers materials, and a surface soil at six different equilibrium concentrations over a concentration range from 0.001 mg/L to 1.0 mg/L. A knowledge of the sorption coefficients of these fuel components and solvents is necessary to predict the transport of these chemicals through ground water systems and ultimately to rivers, lakes, and estuaries. Sorption on oxides and surface soils was found to be pH-dependent with decreased sorption at high pH. Increased ionic strength showed a slight increase in sorption on surface soils and some oxides. Aquifer materials sorbed small amounts of (<3..mu..g/g) of the nonpolar organics. Sorption coefficients for two nonpolar sorbates were determined on seven different aquifer materials. K/sub oc/ varied by a factor of 10 over the aquifer material sorbents. Various sorbent chemical and physical properties, in addition to organic carbon, were measured to discover any correlations between the properties and sorption coefficients. No predictive relationship was found between the sorption coefficient and selected chemical/physical properties of the sorbents. Since the K/sub oc/ concept failed for the aquifer materials studied here and other predictive relations were not found, sorption coefficients must be determined for each aquifer material occurring at a contaminated site. These coefficients must be used in contaminant transport calculations.

Research Organization:
College of William and Mary, Williamsburg, VA (USA)
OSTI ID:
6603409
Country of Publication:
United States
Language:
English