Electronic Thesis and Dissertation Repository


Master of Engineering Science


Chemical and Biochemical Engineering


Dr. Ajay K. Ray

2nd Supervisor

Dr. Ernest K. Yanful

Joint Supervisor


The improvement of photocatalyst efficiency in utilizing the majority of wavelengths in the solar spectrum, an abundant natural resource, presents the next step in the large scale application of photocatalysis for the treatment of dissolved organic and inorganic pollutants in wastewater. In this study, a composite catalyst of TiO2 and Graphene synthesized by a hydrothermal treatment method is used to photo-reduce Zn2+, the most abundant heavy metal found in combined sewer overflows (CSOs). The performance of this composite catalyst was assessed under various process conditions such as pH, light intensity, catalyst loading and light source. The TiO2-Graphene composite catalyst showed a 14.0 ± 1.0 % increase in adsorption capacity of the model compound as compared to pure TiO2 at neutral pH. Also, a 19.2 ± 0.04 % increase in the photoactivity for the reduction of Zn2+ was recorded under solar light conditions using TiO2-G photocatalyst as compared to bare TiO2 when reaction rate constants are compared. This enhancement is a result of the availability of more sorption sites, decrease in bandgap of the TiO2, and effectiveness of the charge separation in the TiO2-G composite catalyst.