Authors: Mphilisi M Mahlambi Ajay K Mishra Shivani B Mishra Rui W Krause Bhekie B Mamba Ashok M Raichur
Publish Date: 2011/08/19
Volume: 110, Issue: 2, Pages: 847-855
Abstract
Titania TiO2 nanophotocatalysts with different phases prepared using a modified sol–gel process were employed in the degradation of rhodamine at 10 mg L−1 concentration The degradation efficiency of these nanophotocatalysts was compared to that of commercial Degussa P25 titania It was found that the nanocatalysts calcined at 450 °C and the Degussa P25 titania had similar photoreactivity profiles The commercial Degussa P25 nanocatalysts had an overall high apparent rate constant of K app of 0023 min−1 The other nanocatalyst had the following rate constants 0017 00089 0003 and 00024 min−1 for 450 500 550 and 600 °C calcined catalysts respectively This could be attributed to the phase of the titania as the anatase phase is highly photoactive than the other phases Furthermore characterisation by differential scanning calorimetry showed the transformation of titania from amorphous to anatase and finally to rutile phase SEM and TEM characterisations were used to study the surface morphology and internal structure of the nanoparticles BET results show that as the temperature of calcinations was raised the surface area reduced marginally Xray diffraction was used to confirm the different phases of titania This study has led to a conclusion that the anatase phase of the titania is the most photoactive nanocatalyst It also had the highest apparent rate constant of 0017 min−1 which is similar to that of the commercial titania
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