Synthesis of iron oxide microparticles with fern leaf morphology: Assessment of the RY-145 azo-dye adsorption

Abstract

New particulate ceramic materials with outstanding properties are needed for several technological applications. In this work, multibranched hematite (α-Fe2O3) has been synthesized by tuning the experimental conditions for obtaining dendritic microparticles with the morphology of fern leaves. Variations of temperature, precursor (K3[Fe(CN)6]) concentration, and time were performed to synthesize dendritic hematite with the best fractal morphology. These materials were characterized structurally and morphologically by X-ray powder diffraction and electron microscopy (SEM and TEM). In addition, the composition was studied by X-ray dispersive energy analysis (EDX). The well-formed multibranched sample was additionally analyzed by infrared (IR) and Raman spectroscopies, thermal analysis, and N2 gas adsorption at 77 K. Finally, this multibranched sample was evaluated as an adsorbent for the removal of an azoic dye (Reactive Yellow-145: RY-145) under mild conditions (25 °C, atmospheric pressure) and pH 3.5. The results showed the interesting potentiality of this multibranched α-Fe2O3 for the adsorption of azo dyes and revealed the high stability of the adsorbent particles. However, the adsorption capacity of the solid is moderately low (13 – 32 mg/g), and it is worth improving this parameter. A pseudo-second order kinetic model was well adjusted, revealing an external adsorption of RY-145 on multibranched hematite with possible chemisorption.