Adsorption of Methylene Blue Dye on Hydrothermally Prepared Tungsten Oxide Nanosheets

Methylene blue (MB) dye was successfully adsorbed on hydrothermally prepared tungsten oxide nanosheets. SEM, XRD, FTIR and EDS were used for characterization of the prepared powder. Different parameters affecting the adsorption process such as, contact time, tungsten oxide dose, MB concentration, pH and temperature were investigated. The experimental data were fitted by first, second-order kinetic and intra-particle diffusion models in order to detect the kinetic of adsorption process. The second-order model is providing the best description of MB adsorption onto WO3.H2O. Adsorption equilibrium data obtained from Langmuir, Freundlich and Tempkin isotherm models, showed that the dye uptake is chemisorptions process. Thermodynamic data reveals that the adsorption reaction is exothermic and spontaneous. The effect of different crystalline phases of tungsten oxide nanosheets was investigated. Hydrated form WO3·H2O nanosheets show high adsorption performance, while the adsorption was poor in case of non-hydrated structure WO3 nanosheets.