Graphene Oxide–TiO2 composite materials for photocatalytic degradation of organic pollutants in water treatment

Abstract

The increasing presence of recalcitrant organic pollutants in water bodies has driven the development of advanced treatment technologies capable of promoting effective degradation beyond conventional processes. In this study, a graphene oxide (GO)–titanium dioxide (TiO2) composite was synthesized via a chemical route and evaluated for photocatalytic degradation of methylene blue under UVC irradiation. Graphene oxide was produced by electrochemical exfoliation of graphite, followed by incorporation into TiO2 at 5 wt.% to form the TiO2:GO5 composite. Structural and morphological characterizations by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and FTIR confirmed the formation of anatase-phase TiO2 and successful integration of GO without secondary phase formation. Photocatalytic performance was assessed by monitoring dye concentration decay over 5 h of irradiation. The TiO2:GO5 composite achieved more than 70% methylene blue removal, reaching a final C/C0 value of 0.28, compared to 0.29 for pure TiO? under identical conditions. The degradation followed pseudo-first-order kinetics, with apparent rate constants of 2.302 × 10-¹ h-¹ for the composite and 2.241 × 10-¹ h-¹ for pure TiO2, corresponding to a 2.7% increase in reaction rate. Enhanced initial adsorption and slightly faster absorbance decay were observed for the composite throughout the irradiation period. Although the performance enhancement is moderate, the incorporation of graphene oxide improved charge separation and adsorption behavior without requiring high-temperature calcination. These findings demonstrate that GO modification represents a viable strategy to enhance TiO2 photocatalytic activity under energy-efficient synthesis conditions, highlighting its potential application in advanced water and wastewater treatment systems.