Magnetic α-Fe2O3/MCM-41 nanocomposites: Preparation, characterization, and catalytic activity for methylene blue degradation

• Published in: Journal of colloid and interface science 2012-07, Vol.377 (1), p.184-190
• Main Authors: Ursachi, Irina, Stancu, Alexandru, Vasile, Aurelia
• Format: Article
• Language: English
• Subjects: ambient temperature; aqueous solutions; Catalysis; catalysts; catalytic activity; Cetrimonium Compounds - chemistry; Chemistry; Colloidal state and disperse state; Degradation; Exact sciences and technology; Ferric Compounds - chemical synthesis; Ferric Compounds - chemistry; General and physical chemistry; Hematite; Hydrogen peroxide; Hydrogen-Ion Concentration; hysteresis; Magnetic nanoparticles; Magnetic properties; Magnetics; MCM-41; Methylene blue; Methylene Blue - chemistry; nanocomposites; Nanocomposites - chemistry; nitrogen; Particle Size; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Porous materials; scanning electron microscopy; silica; Silicon Dioxide - chemical synthesis; Silicon Dioxide - chemistry; Surface Properties; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Ultrasonic irradiation; wastewater; X-ray diffraction
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2012.03.066

[Display omitted] ► α-Fe2O3/MCM-41 nanocomposites were synthesized by ultrasound-assisted method. ► α-Fe2O3/MCM-41 nanocomposites showed activity for sono-degradation of methylene blue. ► Ultrasonic irradiation of catalyst promotes very reactive hydroxyl radicals formation. ► MB could be degraded at room temperature in short time. ► α-Fe2O3/MCM-41 catalyst can be removed easily from the solution by centrifugation. Catalysts based on nanosized magnetic iron oxide stabilized inside the pore system of ordered mesoporous silica MCM-41 have been prepared. The obtained materials were characterized by powder X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and N2 adsorption–desorption isotherm. XRD analysis showed that the obtained materials consist from the pure hematite crystalline phase (α-Fe2O3) dispersed within ordered mesoporous silica MCM-41. Magnetic measurements show that the obtained nanocomposites exhibit at room temperature weak ferromagnetic behavior with slender hysteresis. The catalytic activity of the magnetic α-Fe2O3/MCM-41 nanocomposites was evaluated by the degradation of methylene blue (MB) aqueous solution. For this purpose, an ultrasound-assisted Fenton-like process was used. The effect of solution pH on degradation of MB was investigated. The results indicated that US–H2O2–α-Fe2O3/MCM-41 nanocomposite system is effective for the degradation of MB, suggesting its great potential in removal of dyes from wastewater. It was found that the degradation rate of MB increases with decrease in the pH value of the solution.