Photocatalytic oxidation of gaseous 1,2-dichlorobenzene using photonic titania (inverse opal) on optical fibers in a monolith configuration

Macroporous photonic band-gap titania with inverse opal topology was fabricated on optical fibers using polystyrene templates and sol–gel chemistry. The photonic character of the inverse opal titania was characterized using X-ray diffraction and UV absorbance measurements. The fibers were bundled into a monolith reactor and used to degrade a gaseous pollutant, 1,2-dichlorobenzene (DCB). The process was conducted in a semi-batch system with UV radiation being conducted through optical fibers. Experimental parameters such as polystyrene template size, UV light intensity, fiber distribution pattern and feed flow rates were varied. The reaction rate constant increased with increasing feed flow rate and UV intensity. Rate constants were reaction-limited above a flow rate of 50 mL/min and the intrinsic rate constant reached at asymptotic value above the UV intensity of 60 mW/cm2 in the lab-scale reactor. Computational fluid dynamic (CFD) simulations identified flow bypassing in the reactor, which was rectified by rearranging the fibers within the reactor.