Synthesis of activated carbon from walnut wood and magnetized with cobalt ferrite (CoFe2O4) and its application in removal of cephalexin from aqueous solutions

Abstract

The aim of this study was to synthesize activated carbon from low-cost material and then magnetize it with CoFe2O4 nanoparticles for evaluating its efficiency in the removal of cephalexin from aqueous media. The physical and structural properties of the synthesized adsorbent were analyzed by SEM, BET, XRD, and VSM techniques. In addition, the effect of parameters, including pH, the concentration of cephalexin, adsorbent dose, and contact time, were studied to determine the equilibrium adsorption process isotherms and kinetics. The results of this study showed that the removal efficiency of cephalexin increases with increasing contact time and adsorbent dose and decreases with increasing pH and the initial concentration of cephalexin. As the concentration of antibiotics increased from 50 to 250 mg/L, the removal efficiency of cephalexin decreased from 96.8% to 36.1%. Optimal conditions for cephalexin removal were obtained at pH = 3, time = 30 min, antibiotics concentration = 50 mg/L, and adsorbent dose = 2 g/L. Cephalexin antibiotic adsorption process follows the Freundlich isotherm (R2 = 0.9817) and pseudo second-order kinetics (R2 = 0.939). Although the removal of cephalexin increases with increasing adsorbent dose, the amount of cephalexin adsorbed per unit mass of adsorbent (qe) decreases from 27.5 to 18.3 mg/g from 0.25 to 2.5 g/L of activated carbon. The present study showed that magnetized low-cost material activated carbon, in addition to having properties such as rapid and easy separation, has a high potential for cephalexin adsorption.