Magnetic carbon-biomass from the seeds of Moringa oleifera@MnFe2O4 composite as an effective and recyclable adsorbent for the removal of organic pollutants from water

Abstract

In the current industrial scenario, the dye molecules are the most rigorous contributors to water pollution, and the removal of these pollutants becomes a problematic task. Carbon adsorbents have been used as superior materials for the water/wastewater treatment process. However, the adsorption system could not use the pristine carbon materials in practical applications as it causes significantly less efficiency in adsorption. Conversely, the tuning of carbon with magnetic materials have been employed. Herein, a magnetically retrievable adsorbent was successfully fabricated using carbon-biomass from the seeds of Moringa oleifera and manganese ferrite viz.; MnFe2O4@MOAC. The organic dyes such as Reactive Blue 4 (RB4), Indigo Carmine (IC) and Acid Blue 158 (AB158) were chosen as the adsorbates for this study, and MnFe2O4@MOAC shows the adsorption efficiency of 32.45, 33.53 and 35.27 mg/g, respectively and the maximum adsorption observed in the pH range of ~3. The adsorption followed the Freundlich isotherm and the pseudo-second-order kinetics. The adsorption thermodynamics revealed that the process was endothermic and spontaneous. The fabricated adsorbent was recovered and reclaimed in five successive cycles of adsorption. Electrostatic attractions, hydrogen bonding and π-π interactions were the essential mechanisms involved in the adsorption. The newly fabricated bio-mass could be visualized as a capable adsorbent for water/wastewater treatment process since the MnFe2O4@MOAC possesses high removal efficiency towards dye molecules.