Research On The Preparation Of Ferrite Composite And Adsorption Performance For Gentian Violet

Dyes and their degradation products?aromatic amines? present high color, high toxicity and even carcinogenic and toxic due to its complex chemical structure. Therefore, the treatment of dye wastewater to eliminate such pollution is necessary. Adsorption is an effective and simple method, which has been widely employed to remove dyes from aqueoussolution due to the simplicity of design, ease of operation, and insensitivity to toxic substances.The CoFe₂O₄/AC?activated carbon?, MgFe₂O₄/ANTC?anthracite? and MgFe₂O₄/CB?carbon black? were synthesized via a facile one-step low-temperature refluxing route, and solvothermal method, respectively. The as-prepared composites were characterized by vibrating sample magnetometer?VSM?, X-ray diffraction?XRD? and Fourier transform infrared spectroscopy?FT-IR?. The adsorptive property of the composites for gentian violet?GV? dyes removal was studied.Results indicate that ionic strength nearly has no influence on the adsorption of gentian violet by Co Fe2O4 /AC. Adsorption of GV onto CoFe₂O₄/AC was investigated in a batch system. The results show that the removal efficiency of gentian violet can be acheived above 95%with the initial pH of 10.24 and the adsorbent dosage of 0.1 g, while the time of equilibrium adsorption is 3 h. The adsorption of GV by CoFe₂O₄/AC conformed to the Langmuir adsorption model, which suggested that the adsorption is monolayer coverage and the maximum monolayer adsorption capacity of GV onto CoFe₂O₄/AC was 184.2 mg/g. In addition, the mean free adsorption energy was calculated as 0.537 kJ/mol, which is very likely that GV adsorption onto CoFe₂O₄/AC is physical in nature. The thermodynamic behavior analysis indicates that the adsorption ofgentian violet is a spontaneous 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. After regenerated five times by acidic methanol solution, CoFe₂O₄/AC still remains good ability of adsorption of gentian violet and the adsorption capacity can up to 77.89 mg/g. When the initial pH is 10.30 and the adsorbents dosage is 40 mg, the removal efficiency of gentian violet can be achieved 90%.The adsorption of GV by MgFe₂O₄/ANTC can be conformed to both the Langmuir adsorption model and Frendlich adsorption model, which suggested that the adsorption is monolayer coverage and the maximum monolayer adsorption capacity of GV onto MgFe₂O₄/ANTC was calculated as 192.68 mg/g. The mean free sorption energy was calculated as 0.416 kJ/mol, which is very likely that GV adsorption onto MgFe₂O₄/ANTC is physical in nature. The thermodynamic behavior analysis indicates that the adsorption of gentian violet is a spontaneous and exdothermic process. The adsorption processes could be well fitted with the pseudo-second-order kinetic model, and the whole adsorption process was mainly controlled by intraparticle diffusion. After regenerated five times of MgFe₂O₄/ANTC adsorbed GV by acidic methanol solution, it could remain good ability of adsorption of gentian violet.Adsorption of GV onto MgFe₂O₄/CB can be acheived above 92.3% with the neutral condition and the adsorbent dosage of 40 mg.The adsorption equilibrium was well described by the Langmuir isotherm model with maximum adsorption capacity of 126.71 mg/g of gentian violet on MgFe₂O₄/CB. The observed increase in adsorption with increasing temperature suggests that the adsorption of dye on MgFe₂O₄/CB is endothermic in nature. From thermodynamic parameters such as enthalpy, free energy and entropy changes were calculated and these values show that the adsorption of gentian violet is a spontaneous endothermic and physisorption process. Gentian violet adsorption followed pseudo-second-order rate kinetics. In addition, the whole adsorption process was jointly controlled by external mass transfer and intraparticle diffusion. After regenerated five times by acidic methanol solution, MgFe₂O₄/CB still remains good ability of adsorption of gentian violet.