Photocatalysis in microreactors

A photocatalytic microreactor with immobilized titanium dioxide as photocatalyst and illuminated by UV-A light emitting diodes was constructed and tested for the degradation of the model substance 4-chlorophenol. The microreactor consisted of 19 channels with a cross-section of approximately 200 μm×300 μm. Intrinsic kinetic parameters of the reaction could be determined and mass-transfer limitations for the employed operating conditions could be excluded by calculating appropriate Damköhler numbers. Photonic efficiencies for the degradation of 4-chlorophenol are provided. The illuminated specific surface of the microstructured reactor surpasses that of conventional photocatalytic reactors by a factor of 4–400.