Magnetic mesoporous clay adsorbent: Preparation, characterization and adsorption capacity for atrazine

Fe3O4/sepiolite magnetic composite (MSEP) was prepared by chemical co-precipitation method in air and used as adsorbent to remove atrazine from aqueous solution. The composite was characterized by using X-ray diffraction, X-ray fluorescence, specific surface area, Fourier transform infrared spectroscopy, scanning electron microscope, magnetic hysteresis loop and zeta potential measurements. The results show that the specific surface area, average pore diameter and pore volume increased from 70.92 m(2)/g, 6.4441 nm and 0.1143 cm(3)/g for the natural sepiolite (NSEP) to 112.44 m(2)/g, 8.6703 nm and 0.2437 cm(3)/g for MSEP because of the loading of Fe3O4 particles on the surface of sepiolite particles. The electrokinetic property of sepiolite in an aqueous solution was promoted and the isoelectric point of MSEP was obtained at pH 7.7. The values of saturation magnetization, remanent magnetization and coercivity for MSEP were 31.82 emu/g, 1.12 emu/g and 11.77 Oe, respectively. The adsorption experiments of atrazine onto MSEP show that the adsorption process followed the Langmuir isotherm model and the maximum adsorption capacity can reach 15.9 mu g per unit BET surface area of adsorbent. (C) 2014 Elsevier Inc. All rights reserved.