| dc.description.abstract | Iron oxide and iron oxide-zeolite magnetite composites have been prepared by co-precipitation method at temperature 70 ˚C. The magnetite composite were prepared with ratios of 1:1, 1:2, and 1:3 by weight. The magnetite composites were made to obtain an adsorbent that can be responsive to magnetic field so that it can be separated by simple magnetic procedure. The result from X-ray diffraction characterization showed a similarity of diffraction peak of zeolite with specific peak in PCDFWIN program database no 29-1257, which was mordenit. In addition, iron oxide and magnetite composites had a same peak with specific peak in PCDFWIN program database no 19-0629, which was iron oxide of magnetite (Fe3O4). Characterization using scanning electron microscope showed microstructure of zeolite that have small pores, while magnetite composite revealed iron oxide particles that cover and surrounded the pores of the zeolite. Adsorption experiment using surface response method showed that adsorption capacity of Cr(III) and Cr(VI) with composite did not increase significantly. However, the composite samples were capable in separating the composite adsorbent from the adsorbate medium using permanent magnet. The optimum capacity of adsorption occurred in 0.5 g of adsorbent, adsorption time of 12 hours, and initial concentration of 60 ppm | en |
