Magnetic Composites Based on Cobalt Ferrite, Vermiculite, and Rice Husks: Synthesis and Properties

Magnetic sorbents show promise in technologies for they can be removed with a magnet after sewage waters are decontaminated. Sol–gel strategy was implemented to manufacture new cost-efficient composite sorbents based on cobalt ferrite, vermiculite, and alkaline rice husks hydrolyzate. An alkaline solution of the rice husks hydrolyzate was added with a suspension of Co[Fe 2 O 4 ] nanoparticles, and then neutralized with vermiculite suspension in 12% hydrochloric acid. The thus-manufactured magnetic sorbents were characterized by X-ray powder diffraction, IR and positron annihilation spectroscopy. Their physical and chemical characteristics were determined by low-temperature nitrogen physisorption as well as by adsorption of Methylene Blue dye in solution. The morphology of composites was identified by means of scanning electron microscopy. The bulk and surface elemental compositions of samples were found by energy dispersive fluorescent analysis. The magnetic saturation and coercivity of the samples were measured in the range of 0 to 2500 Oe fields. Sorbent particles were easily separated from solutions with a magnet. The sorbents showed high adsorption capacity with respect to Methylene Blue dye. The effect of the sodium phenyl siliconate template on the magnetic properties of the composites was elucidated.