SORPTION OF NONPOLAR ORGANIC-COMPOUNDS, INORGANIC CATIONS, AND INORGANIC OXYANIONS BY SURFACTANT-MODIFIED ZEOLITES

Treatment of natural zeolites with cationic surfactants yielded sorbents with a strong affinity for nonpolar organics and for inorganic oxyanions, and caused little decrease in the zeolite's sorption of transition metal cations. Two zeolites modified with hexadecyltrimethylammonium or methyl-4-phenylpyridinium remained chemically stable in aggressive aqueous solutions and organic solvents. The modified zeolites sorbed benzene, toluene, p-xylene, ethylbenzene, 1,1,1-trichloroethane, and perchloroethylene from aqueous solution via a partitioning mechanism; sorption affinity was in the order of the sorbates' octanol-water partition coefficients. Zeolites with or without surfactant treatment strongly sorbed Pb2+ from solution. Surfactant-modified zeolite also sorbed chromate, selenate, and sulfate from solution; the mechanism appears to be surface precipitation of a surfactant-oxyanion complex.