Photocatalytic reactions over TiO2 supported on porcelain spheres

G. PIPERATA; J.M. MEICHTRY; M.I. LITTER

PROGRESS IN POLYMER SCIENCE

Springer Verlag

Lugar: Berlín; Año: 2004 vol. 128 p. 303 - 308

0340-255X

Results of immobilisation of TiO2 on low-cost porcelain beads and the resulting photocatalytic activities of the samples are presented. A very simple technique for immobilisation by immersion in a TiO2 suspension, previously acidified to pH 2.5, followed by calcination at 450 oC, was used. After a vigorous washing with a water jet, no detachment of the catalyst was observed at the end of the fixation process. Reasons for the stability of the material are discussed. The crystallographic nature of P-25 was not affected after attachment to the porcelain surface. The beads were submitted for 100 h to turbulent regimes corresponding to Re numbers of 100 and 400 in a recirculating system. The effect of the recirculation flow was carefully examined to evaluate the degree of detachment of the catalyst from the support and to assess how the treatment influences on the activity of the supported catalyst. For this, photocatalytic tests were performed on two model compounds, 4-chlorophenol and potassium dichromate in the presence of ethylenediaminetetraacetic acid, and results were compared with those of untreated beads. A good activity remained in the beads even after washing for more than 100 hours in a turbulent regime (both Re 100 and 400). The activity of particles detached from the support by ultrasonication was also compared with that of the pure precursor.