Mesoporous Jarosite/MnO2 and Goethite/MnO2 Nanocomposites Synthesis And Application for Oxidation of Methylene Blue

Abstract

Jarosite-MnO₂ and goethite-MnO₂ nanocomposites are synthesized for the first time via a simple in situ reduction-oxidation process using iron(II) sulfate heptahydrate, potassium permanganate, and sodium hydroxide with cetyltrimethylammonium bromide (CTAB) as a template. The prepared materials are well characterized by different analytical techniques such as X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and surface area studies. The reactivity of these catalysts towards a methylene blue solution is examined. The results indicate that a higher N-demethylation rate of methylene blue (MB) is available under the goethite/MnO₂ catalyst to thionin in acidic circum. Also goethite/MnO₂ as a heterogeneous Fenton-like catalyst is highly effective for the decolorization and degradation of MB in the presence of H₂O₂. The degradation efficiency is best (90% within 60 min) with initial concentrations: 31.25 mg/L of MB, 1.5 ml of hydrogen peroxide, and 0.02 g of goethite/MnO₂ as the catalyst. The presence of goethite particles leads to the improvement of the catalytic properties, thus indicating that the catalyst is potentially useful in the treatment of wastewater.