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

In this study, a novel method for immobilization of the titania catalysts o n a metallic support (SS304) was developed by using the chemically inert an d photostable fluororesin - PTFE (TEFLON) as a binder. Response surface met hodology (RSM) was applied to obtain the optimum conditions for preparing t he 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 ha ve been characterized by SEM and XRD. Results showed that the immobilized t itania was mainly exposed on the top surface of the metallic support and st ill kept the original crystal phase (mainly anatase) of TiO2 powder. The ph otocatalytic activity of the immobilized TiO2 catalysts was assessed throug h the photocatalytic degradation of 4-chlorophenol. For this reaction, by c omparing the apparent rate constants for COD and TOC removal, the immobiliz ed titania was about twice more efficient than UV photolysis, but it was le ss efficient than the suspended TiO2 system with similar reaction condition s. Nevertheless, from an application point of view, the novel method develo ped had several advantages such as easy preparation at a relatively low tem perature (120 degrees C), no need to filtrate, and providing more flexibili ty in catalyst configuraion for photoreactor. In addittion, the resulting i mmobilized titania photocatalyst was highly stable. Such advantages may act ually compensate the drawback of a lower activity.