Perceptive removal of toxic azo dyes from water using magnetic Fe3O4 reinforced graphene oxide–carboxymethyl cellulose recyclable composite: Adsorption investigation of parametric studies and their mechanisms

Abstract

A magnetic FGC composite was prepared using Fe3O4 particles and graphene oxide–carboxymethyl cellulose which were blended as the source materials. The adsorptive interactions of FGC matrix with dye molecules like Congo Red (CR), Acid Red 1 (AR1) and Reactive Red 2 (RR2) were examined and explained through various analytical techniques. The optimum conditions for the adsorption of dyes include the initial concentration of dyes (50 mg/L), volume of dyes (50 mL), adsorbent dosage (100 mg) and solution pH (3-6). In these conditions, the FGC showed extreme adsorption efficiency of 45.09, 47.32 and 46.21 mg/g for the removal of CR, AR1 and RR2 dye molecules, respectively. The Freundlich isotherm data shows better fit for dye molecules adsorption. The thermodynamic results confirmed the endothermic and spontaneous nature in adsorption. The mechanism of CR, AR1 and RR2 dyes adsorption on FGC composite follows the interactions such as electrostatic attraction, hydrogen bonding, π−π stacking, and surface complexation. The FGC composite was regenerated over 65% after five consecutive cycles using an aqueous 0.1 M NaOH solution. The FGC composite showed an enhanced adsorption capacity for the removal of toxic azo dyes. Hence, the prepared composite could be used as a potential adsorbent for the removal of dye molecules from contaminated water.