Magnetic modification of Ghassoul

Abstract

Ghassoul, a unique mixture of stevensite and sepiolite, comes from the only known deposit in the world, Jbel Ghassoul inMorocco. Ghassoul was found to be very good adsorbent of metal and organic pollutants and it can be also used for the preparation of cordierite ceramics. The presented study is focused on the preparation and study of magnetically modified Ghassoul. The microwave–assisted precipitation of iron oxides from water solution using FeSO4.7H2O as precursor was used for preparation magnetic form ofGhassoul. Both the native material and the prepared magnetic Ghassoul were characterized by chemical and phase analysis (X-ray fluorescence analysis, total content of selected elements after acid decomposition in acid mixture was determined by atomic absorption spectroscopy with flame atomization and atomic emission spectrometry with inductively coupled plasma, content of Fe(II) according to the Czech standard CSN 722041 and powder X-ray diffraction methods). The magnetic iron oxides on the Ghassoul surface were observed by transmission electron microscope. Saturation magnetization and coercive field were obtained from hysteresis loops measured using the Vibrating Sample Magnetometer. Verification of adsorption properties was carried out with Cd2+ ions. It was proved that the prepared magnetically modified clay minerals contained iron oxides nanoparticles of γ–Fe2O3 and Fe3O4 which were very strongly bound on the surface. The magnetic measurements have detected that saturation magnetization was approximately two orders higher and coercive field a little bit lower in comparison with thenatural clay sample. The results show that the presence of magnetic iron particles on Ghassoul surface did not affect theadsorption properties negatively but make magnetic separation of adsorbent from aqueous solution possible.