Towards a precise assessment of the performance of supported photocatalysts for water detoxification processes

Citation
Rl. Pozzo et al., Towards a precise assessment of the performance of supported photocatalysts for water detoxification processes, CATAL TODAY, 54(1), 1999, pp. 143-157
Citations number
16
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CATALYSIS TODAY
ISSN journal
09205861 → ACNP
Volume
54
Issue
1
Year of publication
1999
Pages
143 - 157
Database
ISI
SICI code
0920-5861(19991126)54:1<143:TAPAOT>2.0.ZU;2-F
Abstract
The performance of Degussa P-25 titanium dioxide photocatalyst in a water e nvironment and two different forms of operation was studied. The finely div ided powder was used in a suspended bed (slurry) reactor, and the same cata lyst was physically supported on quartz sand and employed in a fluidized be d reactor. Both reacting systems were operated under conditions of a fully irradiated photoreaction space (FLP reactor) and the comparison was made fo r the same mass concentration of catalyst per unit reactor volume (250 ppm) using different combinations of bed expansion and surface coverage of the support. A tubular black light lamp was placed inside an annular reactor, w here the photocatalytic oxidation of a model compound (oxalic acid) was inv estigated. Results were analyzed in terms of initial reaction rates per unit reactor v olume and per unit of the liquid phase volume inside the reactor. Likewise, apparent quantum efficiencies were evaluated for the initial conditions, u sing the concept of apparent captured radiation power. It was found that th e efficiency of the slurried photocatalyst is approximately five times larg er than in the supported form. Among the different fluidized bed operations the highly expanded bed, with 100% coverage of the support surface, was fo und to be the most convenient condition for the immobilized titania. (C) 19 99 Elsevier Science B.V. All rights reserved.