Removal of Acid blue 113 from aqueous medium using a novel magnetic adsorbent derived from activated carbon fiber

In this study, adsorption of Acid Blue 113 dye (AB113) onto the magnetically activated carbon fibre (ACF) with iron oxide nanoparticles (ACF/Fe3O4) was evaluated. Effects of different reaction conditions, e.g. contact time, pH, AB113 ion concentrations, and temperature, were also studied. The batch adsorption studies revealed that the AB113 ions reached equilibrium at 90 min. From the results, it was clear that when the initial AB113 concentration was 10 mg/L and pH was 3, a 100% removal percentage was achieved in the presence of ACF/Fe3O4 (a dosage of 0.8 g/L) at 30. The thermodynamic parameters revealed that the process is endothermic, spontaneous, and thermodynamically favourable. Under the best experimental conditions, the maximum adsorption capacity was obtained to be 121.4 and 112.2 mg.g(-1), according to the nonlinear and linear Langmuir model. Adsorbent reuse was performed in six consecutive cycles, and the results showed high adsorbent efficiency in all cycles. Linear and nonlinear forms of six isotherm models and four kinetic models were investigated, and the equilibrium data, in addition to regression coefficient (R-2), were matched with four error coefficient models. As a result, due to the high R-2 and the lower error coefficient, the equilibrium data follow the Langmuir isotherm and Pseudo-second-order (PSO) kinetic with both linear and nonlinear models. The adsorption mechanism can be explained through pi-pi bonds, hydrogen bonds, and electrostatic interactions. The prepared ACF/Fe3O4 presented excellent adsorption capacity for the removal of AB113, demonstrating its viability for removing this contaminant from the aqueous medium.