A new continuous flow-through structured reactor for the photodegradation of aqueous contaminants

A flow-through photo reactor with a stainless steel mesh-supported ZnO catalytic disc has been designed in this work. The preparation method of the catalyst includes the use of Triton™ X-100 and methylene blue (MB) in order to enhance the homogeneity of the ZnO and its adhesion to the mesh. The catalysts exhibit a high surface area (∼100 m2/g). The photocatalytic reaction is restricted to the most external non-polar edges of the ZnO nanosheets due to the low pH of the MB solution and to the fact that the polar surfaces are hydrophobic. Despite this, the performance of the flowthrough reactor is superior to that of other micro fluidic systems. The catalyst undergoes a slight deactivation during the reaction, though the activity can be restored, without causing any structural changes, by passing water through the catalyst under UV irradiation. The loss of ZnO through photocorrosion is low, especially when compared to the loss experienced by the same catalyst prepared without using methylene blue.