Abstract

In this work, MgO supported Fe-Co-Mn nanoparticles (MgO-FCM-NPs) are synthesized and utilized as adsorbent for the successful removal of Rhodamine B dye (RhB) from aqueous environments. In the first step, the synthesized MgO-FCM-NPs are identified using scanning electron microscopy (SEM), vibration sample magnetization (VSM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) techniques. In the second step, the effects of different adsorption conditions such as solution pH (3-13), dye concentration (10-120 mg L-1), adsorbent dosage (0.04-0.12 g L-1), temperature (298-318 K) and contact time (20-100 min) are investigated. The pH 7 is found to be the optimized pH and the equilibrium is reached in 60 min for RhB adsorption onto MgO-FCM-NPs. The maximum adsorption capacity of RhB onto MgO-FCM-NPs is found to 1106 mg g(-1) at pH 7, temperature 318 K and contact time 60 min using 120 mg L-1 RhB concentration. The adsorption data is fitted better to Langmuir isotherm model (R-2 = 0.999) in comparison to Freundlich and Temkin equilibrium isotherm models. The n (Freundlich constant) values are in between 1-10, suggesting desirable adsorption of RhB onto MgO-FCM-NPs. Further the adsorption process of RhB onto MgO-FCM-NPs is followed pseudo-second-order kinetics (R-2 = 0.9999). The negative values of Gibbs free energy (Delta G degrees) represents spontaneity of the process and the positive values of enthalpy (Delta H degrees) of RhB adsorption onto MgO-FCM-NPs indicates the endothermic nature. Finally, it is concluded that the MgO-FCM-NPs could be used for effective RhB removal from textile effluents. (C) 2019 The Authors. Published by Elsevier B.V.