Adsorptive removal of gentian violet from aqueous solution using CoFe2O4/activated carbon magnetic composite

• DOI: 10.1016/j.jwpe.2018.11.013
• Publication Date: 2018-11-28T05:49:42Z
• Authors: Yao-Dong Liang; Yong-Jun He; Ting-Ting Wang; Li-Hua Lei
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract CoFe2O4/activated carbon composite (CoFe2O4/AC) was prepared by a facile one-step low-temperature refluxing route. The obtained material was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller surface area method and vibrating sample magnetometer techniques, respectively. The composite was tested as an adsorbent for the removal of gentian violet (GV). The adsorption process was investigated as the functions of ionic strength, temperature, solution pH, adsorbent dosage, contact time and initial GV concentration. The equilibrium adsorption data fitted well to the Langmuir model and the maximum adsorption capacity was found to be 184.2 mg g−1 at 303 K. The remarkable adsorption capacity of GV onto CoFe2O4/AC was attributed to strong π-π interaction and weak electrostatic attraction between GV and CoFe2O4/AC. The thermodynamic analysis suggested that the adsorption of GV on CoFe2O4/AC was a spontaneous, physical and endothermic process. The adsorption processes could be described by the pseudo-second-order kinetic model. The whole adsorption process was jointly controlled by external mass transfer and intraparticle diffusion. Magnetic CoFe2O4/AC with adsorbed GV could be regenerated using acidic ethanol solution and was separable from liquid media using a magnetic field.