Synthesis and characterization of novel manganese oxide nanocorals and their application for the removal of methylene blue from aqueous solution

Novel manganese oxide nanocorals (MONCs) were synthesized, characterized, and successfully used for the removal of toxic methylene blue (MB), as an example of organic dyes, from a model and the real solution. The MONCs were characterized by XRD, scanning and transmittance electron microscopes, and surface area analysis. The results confirm the formation of MONCs as nanocrystalline orthorhombic gamma-MnO2 phase with nanowires with diameters between 20.0 and 40.0 nm. The MONCs used for the removal of MB from aqueous solution and the different parameters that affected the adsorption process were studied and optimized. The adsorption process was studied kinetically and thermodynamically to elucidate the removal mechanism for better efficiency. The results showed that the removal process followed the pseudo-second-order kinetics model, and the spontaneity of the adsorption process at ambient temperatures. Finally, MONCs were used for the removal of MB ions from a wastewater sample, and the result indicated that they were highly efficient at removing the toxic MB. (C) 2015 Elsevier B.V. All rights reserved.