Development of an optical fiber monolith reactor for photocatalytic wastewater Treatment

Abstract

A photocatalytic reactor, which employs a ceramic multi-channel monolith as a support for TiO₂ and bare quartz fibers inserted inside the monolithic channels as both a light-transmitting conductor and a support for TiO₂, was constructed and tested for water treatment by investigating the photocatalytic degradation of o-dichlorobenzene (DCB) and phenanthrene (PHE). This configuration provides a higher surface area for catalyst coating per unit reactor volume compared to the continuous annular reactor (CAR) and optical fiber reactor (OFR). The light distribution profile inside each cell of the monolith is analyzed. Exponential decay of light was observed in propagation along the quartz fiber core and penetration into the TiO₂ film. Optimum thickness of TiO₂ layer on the optical fiber was found to be ≈ 0.4 μm in this study. The kinetics of DCB and PHE degradation were pseudo-first order. The effect of the water flow velocity was investigated and showed that the operation was in the mass transfer control regime. Overall rate constants were extracted from the experimental data; and these were then used to calculate the apparent quantum efficiency of photocatalytic degradation. Greater apparent quantum efficiency was observed for the optical fiber monolithic reactor (OFMR) compared with that of the CAR.