S. Athira , S. Solomon
UNIVERSITY OF KERALA,
India
Keywords: perovskite, titanates, photocatalyst, wastewater treatment
Summary:
Research related to economical and time-efficient synthesis of titanates-based nanoparticles as proficient photocatalyst is timely. The versatility of these nanoparticles is based on their tuneable optical, structural, morphological, and other physical and chemical characteristics, which make them multi-functional materials for various applications. In this work, a comprehensive study was performed to uncover the underlying mechanisms of titanates, to obtain a highly efficient photocatalyst. Titanates based Ba0.5Ca0.5TiO3 (BCT), Ba0.5 Sr0.5TiO3 (BST) and Sr0.5Ca0.5TiO3 (SCT) nanoparticles are successfully synthesized using a low cost modified combustion method. Their structure and morphological and optical properties were analysed using XRD, FESEM, TEM, FTIR, Raman, and UV-Visible spectroscopy. Variations in morphology are noticeable for BCT, BST and SCT NPs. In the case of BCT NPs a rectangle shaped with distinct grain boundary morphology is observed. BST NPs shows a flake shaped morphology but in the case of SCT an irregular shaped morphology and the agglomeration of particles are observed. Adsorption Kinetic mechanism indicates that the adsorption of MB dye was controlled by pseudo second order kinetic model. The positive ΔHo value suggested that the MB dye adsorption is an endothermic reaction. The positive ΔSo value shows the increase in randomness at the solid-solution interface during the fixation of the ions in the dye on the active sites of the adsorbent. The photocatalytic efficiency of these nanomaterials is observed against the removal of methylene blue dye and displayed optimum degradation when exposed to visible light. The as synthesized NPs are smaller nanoparticles having large surface area with more active sites and therefore enhance the photocatalytic activity due to the smaller particle size and wide band gap. The synergistic effect of photolysis is also discussed after studying various parameters. The practical applicability of catalyst was assured from the water quality test and the results show that these titanates are promising materials to remove the contaminants like toxic dyes from industrial effluents and also for waste water treatment.