Enhanced Adsorption and Photocatalytic Removal of Cationic Dyes in Aqueous Solutions by Ternary Graphene Oxide-TiO₂-SiO₂ Nanocomposites.

Abstract

In this study, adsorption is an attractive for the removal of industrial dyes from aqueous simulated wastewaters is reported. The ternary graphene oxide-TiO₂-SiO₂ (GTS) nanocomposite was synthesized by sol-gel method. The as-synthesized nanocomposite was characterized by XRD, BET, FT-IR, SEM-EDAX and TEM analysis. It was found that the synthesised nanocomposite has excellent adsorption and photocatalytic degradation abilities for the removal of cationic dyes, methylene blue (MB) and crystal violet (CV) owing to its homogeneous mesoporosity with a BET surface area of 583.15 m²/g. Furthermore, the adsorption mechanism of these cationic dyes follows pseudosecond-order kinetic model. In addition, the GTS nanocomposite showed maximum adsorption efficiency over MB and CV around 384.62 mg/g and 188.68 mg/g respectively. The thermodynamic parameters (ΔG°, ΔH°, and ΔS°) calculated from the temperature dependent isotherms suggested that the adsorption was spontaneous and endothermic in nature. The study on the reusability of the GTS nanocomposite showed that, even after five succeeding cycles, the capacity of the adsorbent was almost identical.