Capillary microphotoreactor packed with TiO2-coated glass beads: An efficient tool for photocatalytic reaction

A novel capillary microphotoreactor (MPR) packed with TiO2-coated glass beads was developed in this work and its photocatalytic performance was evaluated using degradation of methylene blue (MB) as a model reaction. As compared to conventional wall-coated MPR, the use of glass beads as packing material not only provides a larger surface area for catalyst immobilization and shortens the mass transfer route, but also introduces flow perturbation. An appropriate size of glass beads should be chosen for packing because there is a tradeoff between increased catalysts coating area and decreased light penetration. It was found out that nearly 100 % degradation efficiency could be achieved in 80# glass beads packed MPR within short residence time (20 s), which was more than 2 orders of magnitude larger than value obtained in wall-coated MPR under the same operational conditions. Moreover, the packed MPR showed good durability, which declined by about 17 % after 6 h of operation and then remained stable for next 19.5 h.