EVALUATION OF SORPTIVE PARTITIONING OF NONIONIC POLLUTANTS IN CLOSED SYSTEMS BY HEADSPACE ANALYSIS

An equilibrium headspace technique is shown to be applicable to the determination of sorption equilibria for the nonionic volatile organic compounds toluene and trichloroethylene (TCE). This procedure avoids the problems inherent in other experimental techniques that directly analyze aqueous hase concentration. Such problems include incomplete solid phase separation and subsequent measurements of solute bound to dissolved or colloidal sorbent as free solute. Sorptive partitioning coefficients may be determined by the headspace procedure in the absence of carrier solvents or knowledge of the aqueous concentration of the volatile compounds of concern. Experiments examining the sorption of toluene and TCE onto humic acids, alumina coated with humic acids, and two soil core samples demonstrated the applicability of the headspace technique to sorption studies.