Bare, gold and silver nanoparticle decorated, monodisperse-porous titania microbeads for photocatalytic dye degradation in a newly constructed microfluidic, photocatalytic packed-bed reactor
Monodisperse porous titania microbeads were synthesized by a sol-gel templating protocol. Gold nanoparticles (AuNPs) synthesized by Turkevich and Martin methods 16 and 5 nm in size, respectively and silver nanoparticles (AgNPs) 12 nm in size were decorated onto the primary amine attached titania microbeads. Both size and porous properties of bare or AuNP/AgNP decorated monodisperse-porous titania microbeads were suitable for using them as a photocatalyst in a "Microfluidic, Photocatalytic Packed Bed Reactor (MPPBR)" with reasonable pressure drops in the microflow rate range. Then, a MPPBR system for "continuous photocatalytic dye degradation" was first constructed by slurry packing of bare or AuNP/AgNP decorated titania microbeads into a fused silica capillary 320 mu m in diameter. The photocatalytic activities of bare and AuNP/AgNP decorated titania microbeads were determined in MPPBR using a textile dye, Remazol Black 5 (RB5). The complete removal of RB5 was achieved in continuous mode and an appreciable enhancement in the photoremoval rate of RB5 was observed with the MPPBR containing Martin AuNP decorated titania microbeads. The system constructed can be evaluated as a promising tool for both pre-column and post-column applications involving the removal of coloured contaminants in the assays conducted in micro-liquid chromatography systems. (C) 2016 Elsevier B.V. All rights reserved.