Preparation And Properties Of Magnetic Fenton-like Materials

In order to improve the removal effect of Fe₃O₄ in the Fenton-like reaction system and broaden its application scope,two magnetic Fenton-like materials,pure phase Fe₃O₄and Fe₃O₄/Sn S₂ composites,were prepared as non-homogeneous Fenton-like catalysts based on Fenton-like catalytic oxidation technology,which were used together with H₂O₂to form a Fenton-like catalytic oxidation system with methylene blue simulated wastewater as the target.Various properties of the catalysts were investigated using a variety of characterisation tools such as XRD,SEM,EDS,FT-IR,UV-vis DRS,PL and VSM.The Fenton-like activities of pure phase Fe₃O₄ and Fe₃O₄/Sn S₂ composites under different preparation conditions were compared and analysed.The effects of parameters including catalyst dosage,H₂O₂ addition and p H value on the Fenton-like effect were systematically assessed,the trend of the influence of catalyst preparation conditions was analysed,the reaction conditions for the experiments were determined,and the catalytic degradation effects of the two magnetic Fenton-like materials on methylene blue dye wastewater were investigated and kinetic analyses were performed.The stability of the material was examined through repeatability tests and magnetic recovery performance tests,and free radical quenching experiments and exploration of the oxidation mechanism were carried out.The magnetic Fenton-like material Fe₃O₄ was prepared by co-precipitation and the prepared Fenton-like system of co-precipitated Fe₃O₄ showed a good degradation effect on methylene blue solution.It was shown that the co-precipitated Fe₃O₄ prepared at a water bath temperature of 80℃,a drop acceleration of 2 m L/min of precipitant Na OH solution and a drop volume of 150 m L at a Fenton-like reaction condition of p H 3.0,an H₂O₂ addition of 10 mmol/L and a Fe₃O₄ dosage of 80 mg,achieved a removal rate of97.75%for 100 m L of 4 mg/L methylene blue solution.The degradation process of the Fenton-like oxidation system with Fe₃O₄ was in accordance with the quasi primary kinetics with a kinetic constant of 3.292×10^-2 min^-1.Fe₃O₄/Sn S₂ magnetic composites were prepared for the first time by the alcohol-thermal method using isopropanol as the preparation solution and co-precipitated Fe₃O₄as the carrier composite catalyst Sn S₂ and the Fenton reaction was combined with the photocatalytic effect to enhance the catalytic performance through the synergistic effect of both.The experimental results show that the Fe₃O₄/Sn S₂ materials prepared under the conditions of alcohol heat method,reaction temperature of 180℃,reaction time of 12 h,and Fe₃O₄ and Sn S₂ composite molar ratio of 1:1,at a reaction p H of 3.0,a catalyst dosage of 20 mg and an H₂O₂ addition of 25 mmol/L,the removal efficiency of 200 m L of 20mg/L methylene blue solution was 99.87%in 120 min with a quasi primary kinetic constant of 5.122×10^-2 min^-1.Under neutral conditions,the removal efficiency of 20 mg/L methylene blue was 96.46%,and after five reuses the solution could still be separated by an external magnetic field without any significant reduction in catalytic activity.The results show that the magnetic-like Fenton catalysts prepared by optimizing the preparation conditions:The removal rate of Fenton’s oxidation of methylene blue at 4mg/L by Fe₃O₄ under acidic conditions was 97.75%;the removal rate of Fenton’s oxidation of methylene blue at 20 mg/L by the magnetic Fe₃O₄/Sn S₂ composite was 99.87%under acidic conditions and remained at 96.46%under neutral conditions.The result is a magnetic Fenton-like catalyst Fe₃O₄/Sn S₂ for the efficient catalytic removal of dye contaminants over a wide p H range.