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Synthesis, Characteristics and Kinetic Study of Magnetic-Zeolite Nano Composite for Adsorption of Zirconium

Leila Eskandari and Farshad Kheiri

In this research, magnetic-zeolite nano-and micro-composite adsorbents, including nano-and micro-sized zeolite clinoptilolite and iron oxide were synthesized. Natural clinoptilolite tuff was pre-treated and converted into micro-and nano-particles by using a mechanical method. Then, preparation of iron oxide nano-crystals in the presence of nano-and micro-zeolite was followed. The samples were applied to characterize the adsorbents by X-Ray Diffraction, X-Ray Fluorescence, Fourier-Transform Infra-Redspectroscopy, Derivative Thermo Gravimetry, Scanning Electron Microscopy, Transmission Electron Microscopy, and Vibrating Sample Magnetometry, The nano-and micro-composites were evaluated for Zirconium (Zr) removal from aqueous solutions. The effects of the analytical variables, including pH, initial ion concentration, contact time, and temperature were investigated. The process followed a Pseudo-Second Order (PSO) kinetic model with k2 values of 1.596 and 1.396 meq-1 h-1 for Magnetic Zeolite Nano-Composite (MZNC) and Magnetic Zeolite Composite (MZC), respectively. The saturation magnetization of the nano-composite was measured as 19.50 emu g-1 by which the magnetic separations of the samples were facilitated after the adsorption process. The thermodynamic values of ∆G° and ∆H° represented the endothermic and spontaneous natures of Zr removal.