Characterization and study of a single-TiO2-coated optical fiber reactor

A TiO2-coated optical fiber photoreactor was built and studied in order to optimize different parameters before the development of a multi-optical fiber reactor. The physicochemical properties of the TiO2 film prepared by a sol-gel method on an optical fiber were first determined. A thickness of about 30 nm per layer and a roughness of 2 nm were estimated by ESEM and AFM, respectively. The refractive index of the TiO2 coating was determined by a simulation method. Then, the influences of the film thickness, coating length and coating volume on the light transmission within the fiber were investigated. The intensity of transmitted light was found to decrease exponentially as the volume of TiO2 increased. Afterward, the dependence of the photocatalytic degradation of hydroxybutanedioic acid on the incident light intensity, the TiO2 coating thickness and the coating volume were studied and modeled. The photocatalytic degradation was found to be stabilized above a TiO2 volume of 200 mum(3) for a fiber of 1 mm and 100 mum(3) for a fiber of 0.6 mm. Finally, a multi-fiber reactor was built and its degradation rate of hydroxybutanedioic acid was compared to that obtained in a single-optical-fiber reactor. (C) 2004 Elsevier B.V. All rights reserved.