Book Description

"The objective of this investigation was to evaluate the use of batch type solvent extraction and freeze concentration in recovering trace organic pollutants from water. The work was performed using a simplified water system containing known concentrations of phenol, and natural water systems collected from three sources (Meramec Spring, Gasconade River near Jerome, and Missouri River in Jefferson City) with different levels of pollution. The simplified water system was used to evaluate the effect of the number of extractions, solvent to sample ratio, extraction time, initial organic concentration, pH, and turbidity on solvent extraction; and the effect of volumetric concentration and flash freezing on freeze concentration. The natural water systems were employed to evaluate the practical application of the method, and emphasis was placed on the selection and sequence of solvents, pH adjustment, and effect of turbidity. Benzene and chloroform were the solvents used. The proper selection of solvents and the solvent to sample ratio were the most important factors in the solvent extraction method; the number of sequential extractions and pH adjustment were also important variables. Serial extraction with chloroform and benzene yielded a larger recovery at natural pH than extraction with benzene and chloroform; and extraction with chloroform sequentially at pH 4 and 10 produced a greater recovery than extraction with benzene. The concentration of trace organics in spring and river water was subject to significant seasonal variation. The efficiency of phenol recovery by freeze concentration depended on the volumetric concentration ratio and almost complete recovery was obtained at ratios ranging from 6 to 9"--Abstract, leaf ii.