Preparation and photocatalytic activity of metal-supported resin-bonded titania

In this study, a novel method for immobilization of the titania catalysts on a metallic support (SS304) was developed by using the chemically inert and photostable fluororesin - PTFE (TEFLON) as a binder. Response surface methodology (RSM) was applied to obtain the optimum conditions for preparing the immobilized titania in terms of baking temperature, baking time and the ratio of resin/TiO2. It was found that the optimum conditions for preparing immobilized titania were linked to a baking temperature of 120 degrees C, a baking time of 75 min and a resin/TiO2 ratio of 0.5 with as indicated by the TiO2 loss percentage during ultrasonication. The resulting materials have been characterized by SEM and XRD. Results showed that the immobilized titania was mainly exposed on the top surface of the metallic support and still kept the original crystal phase (mainly anatase) of TiO2 powder. The photocatalytic activity of the immobilized TiO2 catalysts was assessed through the photocatalytic degradation of 4-chlorophenol. For this reaction, by comparing the apparent rate constants for COD and TOC removal, the immobilized titania was about twice more efficient than UV photolysis, but it was less efficient than the suspended TiO2 system with similar reaction conditions. Nevertheless, from an application point of view, the novel method developed had several advantages such as easy preparation at a relatively low temperature (120 degrees C), no need to filtrate, and providing more flexibility in catalyst configuraion for photoreactor. In addittion, the resulting immobilized titania photocatalyst was highly stable. Such advantages may actually compensate the drawback of a lower activity.