Enhanced Fenton-like degradation of methylene blue by magnetically activated carbon/hydrogen peroxide with hydroxylamine as Fenton enhancer

Magnetically activated carbon/gamma-Fe2O3 (AC/gamma-Fe2O3) nanocomposite was evaluated as a potential catalyst for degradation of methylene blue (MB) in the presence of hydrogen peroxide (H2O2) and hydroxylamine (NH2OH). The morphology, magnetic, structure and porous properties of the AC/gamma-Fe2O3 catalyst were characterized by using field emission scanning electron microscopy (FE-SEM), vibration sample magnetometer (VSM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and N-2 adsorption-desorption isotherms. The effect of various parameters such as H2O2 and NH2OH dosages, initial pH value and amount of catalyst on the degradation of MB were investigated. Optimum conditions were determined to be 2.0 g L-1 AC/gamma-Fe2O3, pH 5.0,12.0 mmol L-1 H2O2 and 4.0 mmol L-1 NH2OH. Under these conditions, complete degradation of 100 mg L-1 MB was achieved in 15 min. After seven successive catalytic cycles, the magnetic nanocomposite remained its original catalytic activity. Meanwhile, the high saturation magnetization value (30.3 emu g(-1)) of the AC/gamma-Fe2O3 nanocomposite was favorable for the separation and recycling of the catalyst from the reaction media after the catalytic reactions. (C) 2016 Elsevier B.V. All rights reserved.