MnFe₂O₄/bentonite nano composite as a novel magnetic material for adsorption of acid red 138

Abstract

Magnetic MnFe₂O₄/bentonite nanocomposite was synthesized by chemical co-precipitation method. The product was characterized by X-ray diffraction (XRD) and Scanning electron microscope (SEM). XRD results indicated the presence of free quartz in bentonite. The magnetic ferrite MnFe₂O₄ has spinel structure. It is also found that the presence of bentonite in the magnetic composite has not made any changes in the spinel structure of MnFe₂O₄. SEM images of the sorbent shows nanocomposite with a uniform structure and nanochannels from 0.3 to 0.8 mμ in diameter having a surface area of 130 m² g^-1. The results also revealed that the composite has much higher catalytic activity than the bentonite. The process confirmed very fast kinetic and pseudo-second-order model for acid red 138 (AR138) from aqueous solutions. The adsorption of AR138 was strongly dependent on the pH of the medium, where the removal efficiency increased as the pH decreased in pH 2.

Keywords: Acid Red 138, adsorption, bentonite, magnetic material, nanocomposite