Response surface methodology for optimization of Phenol photo-catalytic degradation using Carbon-doped TiO2 nano-photocatalyst

Abstract

In this research, Carbon-doped TiO₂ nano-photocatalyst is synthesized via sol-gel technique and photo-catalytic degradation of phenol has been studied under ultraviolet and visible light irradiation in a fluidized bed reactor. Various techniques are used to characterize TiO₂ nano-photocatalyst such as X-Ray Diffraction, Fourier transform infrared spectroscopy, Energy Dispersive Spectroscopy and Field Emission Scanning Electron Microscopy. Based on the results, carbon is introduced into titania structure leading to enhanced response towards visible light. Response surface methodology is used to model the effect of various parameters such as pollutant concentration, pH, irradiation time, photo-catalyst content and Carbon to TiO₂ molar ratio. The optimum degradation occurs at pH = 9, catalyst content = 2.5 (g/L), initial phenol concentration = 100 (mg/L), C to TiO₂ molar ratio = 2.5 and irradiation time = 180 min. The results show that phenol photo-catalytic degradation kinetics follows Langmuir-Hinshelwood model very closely at optimal conditions. Phenol degradation is 75 % under ultraviolet irradiation during a 180 min period and 70 % under visible irradiation during a 420 min period. Based on the results, C-TiO₂ nano-photocatalyst can be a good option for phenol removal under visible light irradiation.