Study On The Preparation Of Magnetic Chitosan/Biochar Composite And Adsorption/Degradation Of Methyl Orange

In recent years,with the development of China's dye industry,a large number of dyes have been directly discharged into the water environment,leading to cause serious pollution problems increasingly.The main dye wastewater treatment methods have physical,chemical and biological methods.Among them,the adsorption method as an effective physical treatment method has many advantages such as simple equipment,convenient operation,and easy recycling and reusing for adsorbent.Meanwhile,with the development of processing technology,advanced oxidation technology has been attracted wide attention due to its advantages of wide application range,high processing efficiency,and rapid response.The research on photo-Fenton catalytic technology in treating dyes in water is increasing.The research and development of highly efficient and environmentally friendly materials for the adsorption and catalytic degradation of dyes has always been a hot topic for environmental workers.In this study,a magnetic chitosan/biochar composite??-Fe₂O₃@CPB?and a chitosan modified biochar loaded MnFe₂O₄ composite?Mn Fe₂O₄@CPB?were synthesized.The azo dye methyl orange?MO?was studied as the representative pollutants to investigate the feasibility and effectiveness of the adsorption/degradation treatment of MO.A variety of analytical methods were used to characterize the composition,structure,and morphology of the as-synthesized composite materials.Such as Brunauer-Emmett-Teller?BET?,scanning electron microscopy?SEM?,Fourier transform infrared spectroscopy?FTIR?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?and vibrating sample magnetometer?VSM?etc.The adsorption capacities of?-Fe₂O₃@CPB and MnFe₂O₄@CPB for MO were investigated,and the efficiency of MnFe₂O₄@CPB for catalytic degradation of MO under LED visible light was elucidated.The experimental results indicated that the MO was adsorbed to the?-Fe₂O₃@CPB strongly with maximum sorption capacities of 99.583 mg/g,the removal rate was still up to 78.1%after five repetitions.The maximum sorption capacities of MO for Mn Fe₂O₄@CPB was 134.911 mg/g,the removal rate was 80.6%after five repetitions.Through kinetic and thermodynamic analysis,it was found that the pseudo-second-order kinetics model and the Langmuir-Freundlich isothermal model can effectively describe the process of the adsorption of MO by?-Fe₂O₃@CPB or MnFe₂O₄@CPB.In the removal of MO in aqueous solution by catalytic reaction of photo-Fenton,to 100 ml pH=3.0and the concentration of 100 mg/L MO solution by adding 0.25 g/L MnFe₂O₄@CPB,1 mM H₂O₂,at the room emperature with 50 W LED irradiation 150 min,the MO removal rate can reach99.50%.MnFe₂O₄@CPB was shown stable catalytic activity after five sequential degradation cycles and high removal efficiency for MO.