Photocatalyst Hombikat

Two different photocatalysts, namely, Hombikat UV100 (Sachtleben Chemie) and P25 (Degussa) have been used in batch experiments [443] to compare their ability to degrade the toxic components of a biologically pretreated landfill... 

Regarding Hombikat UV-KX) (micrograph not shown), this is a photocatalyst that tends to form large agglomerates of particles, but given its extremely small primary... 

The reaction progress is monitored ofF-Une by HPLC. Flow rates, residence times and initial concentrations of 4-chlorophenol are varied and kinetic parameters are calculated from the data obtained. It can be shown that the photocatalytic reaction is governed by Langmuir-Hinshelwood kinetics. The calculation of Damkohler numbers shows that no mass transfer limitation exists in the microreactor, hence the calculated kinetic data really represent the intrinsic kinetics of the reaction. Photonic efficiencies in the microreactor are still somewhat lower than in batch-type slurry reactors. This finding is indicative of the need to improve the catalytic activity of the deposited photocatalyst in comparison with commercially available catalysts such as Degussa P25 and Sachtleben Hombikat UV 100. The illuminated specific surface area in the microchannel reactor surpasses that of conventional photocatalytic reactors by a factor of 4-400 depending on the particular conventional reactor type. 

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