| Fe oxyhydroxide-vermiculite complexes are prepared by mixing vermiculite with hydroxy-Fe for 1, 3 and 6 months respectively under the simulated acidic soil conditions. The prepared complexes are characterized by chemical analysis, electron microprobe analysis, x-ray diffraction analysis and differential thermal analysis. The results indicate that the complexes prepared are combinations of substrate vermiculite and Fe-oxyhydroxide coating. The amount of the Fe-oxyhydroxide coating increases with increasing of the reaction duration between vermiculite and hydroxy-Fe. The Fe oxyhydroxide-vermiculite complex prepared by reacting vermiculite with hydroxy-Fe for 3 months is chosen for Cr and As adsorption study. The effects of pH, ionic strength, temperature, initial Cr and As concentration, and adsorption duration on the overall adsorption of Cr and As by Fe oxyhydroxide-vermiculite complex are investigated. Results show that Fe oxyhydroxide-vermiculite complex has strong affinity for Cr and As under experimental conditions. The uptakes of Cr and As on Fe oxyhydroxide-vermiculite complex are influenced by pH, ionic strength, temperature, initial Cr and As concentration, and adsorption duration in the order of the initial concentration of Cr and As>pH> adsorption duration>temperature >ionic strength. Because Fe oxyhydroxide-vermiculite complex displays very strong affinity for Cr and As under all experimental conditions, it is likely to influence the mobility of Cr and As in soil and water.
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