Cr2WO6 nanoparticles prepared by hydrothermal assisted method with selective adsorption properties for methylene blue in water

Cr2WO6 nanocrystallites were prepared using a facile hydrothermal assisted process. The microstructures and preferential adsorption performance for methylene blue (MB) of the prepared nanoparticles were investigated using a solid state reaction resulted in Cr2WO6 crystallites as a baseline. Their structural information were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy, N2–sorption BET surface area, thermogravimetric and differential scanning calorimeters. Results show that the Cr2WO6 nanocrystallines with ~50 nm in size are achieved by calcination at 650 °C for only 2 h using a hydrothermal product as precursor, while the micrometer sized Cr2WO6 crystallites synthesized by the solid state reaction at higher temperature (950 °C) for at least 20 h. For the as-prepared Cr2WO6 nanocrystallines, the adsorption performance were tested using methyl orange (MO), Rhodamine B (RhB) and methylene blue (MB). The adsorption ability was found to be in the order of MB>>RhB>MO owing to electrostatic interactions between the adsorbent and the dye. Results of this study provide a kind of promising alternative adsorbent for color removal from industrial wastewaters.