Photocatalytic Degradation of Methylene Blue Dye by Calcium‐and Magnesium‐Based Silicate Ceramics

Abstract

AbstractPhotocatalytic degradation of Methylene Blue (MB) dye by using Larnite (2CaO.SiO2), Forsterite (2MgO.SiO2), and Diopside (CaO.MgO.2SiO2) under sunlight was investigated in this study. The silicate materials under catalytic examination were synthesized by the sol‐gel assisted combustion route and further characterized by UV‐visible Diffuse Reflectance Spectroscopy (DRS) for the bandgap measurement. The bandgap of as‐prepared silicates was found to be lesser than 3.3 eV. The UV‐visible spectroscopy and Chemical Oxygen Demand (COD) analysis results showed that silicate glass ceramics possess the good capability to degrade methylene blue dye in the presence of sunlight. Further degradation studies under visible and UV light irradiation was carried out and kinetics was plotted in terms of ln(C/C0) vs time for a comparative study. The photocatalytic activity of these ceramics decreases drastically from larnite to forsterite due to the presence of different metal oxides. The superior photocatalytic behavior of larnite (67.2 %, 90 %, and 97 % of MB dye degradation under sunlight, visible light, and UV light respectively), when compared to diopside, corresponds to the higher calcium oxide (CaO) to silica (SiO2) ratio.