Investigation of Adsorptive Properties of Modified Sepiolite as an Efficient Magnetically Recoverable Clay for Removal of Azo Dye from Aqueous Solutions

Abstract In this research, the natural clay of sepiolite (Mg₄Si₆O₁₅(OH)₂·6H₂O) were modified by magnetic metal oxide ofNi_0.5Zn_0.5Fe₂O₄ to obtain an efficient and magnetically recoverable adsorbent (Ni_0.5Zn_0.5Fe₂O₄/sepiolite). The synthesized adsorbent (Ni_0.5Zn_0.5Fe₂O₄/sepiolite) was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV-Vis spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX).In this study, the adsorption properties of the prepared sample was evaluated for the removal of Congo red (CR) dye in aqueous solution and the reusability of the sample was also investigated. The effect of initial dye concentration, pH and temperature on adsorption capacity of modified clay (Ni_0.5Zn_0.5Fe₂O₄/sepiolite) for Congo red were investigated. Also, the results of adsorption kinetic of CR dye in aqueous solution followed pseudo- first order model.

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