Abstract

The removals of Methyl violet from aqueous solutions using the double perovskites BaSr2NbO5.5 are reported. The oxides were prepared using solid state reaction in which the raw materials were mixed initially by either acetone or water. The X-ray diffraction measurements demonstrated that the preparation methods have influenced the cell volume, crystal size and surface area of the oxides. As consequence, the adsorption properties were also affected. The study showed that the prepared oxides have a cubic structure with crystallite size is less than 82 nm. However, the crystallite size of the oxide obtained by wet method (W) is higher than that of the oxide obtained by dry method (D). Consequently, the amounts of the dye adsorbed by BaSr2NbO5.5 (D) were higher than those adsorbed by BaSr2NbO5.5 (W). The maximum removal capacities of Methyl violet are found to be 8.71 and 9.39 mg/g using BaSr2NbO5.5 (W) and BaSr2NbO5.5(D) respectively. The removals of the dye have positive relationship with pH, temperature, the specific surface area and the mass of the oxide.

Keywords: Removal; Methylene violet; Perovskite oxides