Synergy of Magnetite Intercalated Bentonite for Enhanced Adsorption of Congo Red Dye

Abstract

Recently, magnetic separation of adsorbent materials has attracted much attention for abatement of water pollutants. Due to the strong magnetic property and environmental beneficial behavior Fe3O4 NPs were used to modify local bentonite clay. The prepared magnetite intercalated Bentonite clay composite (Fe3O4-AC) structure and magnetic property were confirmed by powder X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The prepared Fe3O4-AC composite has shown a superior adsorption efficiency to Congo red (CR) dye over acid activated bentonite clay (AC). The enhanced adsorption of the Fe3O4 NPs intercalated in the layer of bentonite could be ascribed to the enhanced surface area and the prevention of the activated clay agglomeration. The optimum removal efficiency was analyzed using Response Surface Methodology (RSM) based Box-Benhken Design (BBD). The optimum conditions for maximum adsorption % removal were found to 94.9% at 105 min, 0.6 g Fe3O4-AC composite, 10 mg. L−1, and pH =4. The adsorption isotherms and Kinetics process were indicated that the experimental data are well fitted to Langmuir and pseudo-second-order models.