Application of magnetite nanoparticles modified Azolla as an adsorbent for removal of reactive yellow dye from aqueous solutions

Abstract

In this study, we aimed to remove reactive yellow 160 (RY 160) dye from aqueous solutions, and for this, collected Azolla was modified with magnetite nanoparticles. The size and structure of magnetite modified Azolla nanocomposite were studied by scanning electron microscopy and Fourier-transform infrared spectroscopy. The factors affecting the dye removal efficiency including pH, ionic strength, stirring time, solution volume, and adsorbent weight were investigated using Taguchi fractional orthogonal array design (OA16). The results of adsorption kinetics at 50 and 100 mg L–1 under optimum conditions (pH = 2, ionic strength = no salt addition, the solution volume = 25 mL, stirring time = 10 min and adsorbent weight = 0.15 g) showed that removal of RY 160 was performed through a pseudo-second-order kinetic model (qe = 30.2 mg g–1, R2 = 1). Isotherm models at three contact times of 10, 25, and 50 min showed that adsorption follows the Freundlich model (n = 1.2, KF = 2.3). Reusability experiments under optimum conditions confirmed the removal efficiency of more than 95% after 16 repetitive adsorption usage. The results of real samples showed that this nanocomposite is an effective adsorbent for the rapid removal of RY 160. Low-cost, reusability and fast elimination have made the synthesized nanocomposite as a useful adsorbent in RY 160 removal.