Adsorptive Removal of Methylene Blue from Aqueous Solutions Using Magnetic Fe3O4@C-dots: Removal and kinetic studies

Abstract

The Fe₃O₄@C-dots produced from Elaeagnus Angustifolia, has been applied as an adsorbent for the removal of methylene blue (MB) from aqueous solutions. The prepared Fe₃O₄@C-dots exhibited a noticeably higher adsorption capacity for MB, reported to be 124.39 mg/g when compared to the results of many other documented references. Furthermore, after evaluating the effects of various parameters on the adsorption capacity of Fe₃O₄@C-dots, it was discovered that the adsorption capacity increased with the contact time, pH, and MB initial concentration, respectively. Furthermore, the impacts of pH on adsorption were strongly amplified through pH_zpc. According to the results, electrostatic interactions, hydrogen bonding, and chemical binding comprise the adsorption mechanism between the MB molecules and adsorbent. The MB adsorption was identified through the kinetic studies to be dominated through the model of pseudo-second-order kinetic. Also, the isotherm analysis showed that the adsorption process is consistent with the Langmuir equations. As the Fe₃O₄@C-dots were subjected to recycling, no significant changes were observed throughout the adsorption capacity after five regeneration cycles. Considering how the outcomes indicated the capability of magnetic nanoparticles in performing an effective MB removal, we can recommend the high potential of this adsorbent for the clearance of cationic dyes from wastewater. Graphical abstract