Photocatalysts, fibers

Keywords Inorganic fiber Oxide fiber Silicon carbide fiber Heat resistance Photocatalyst... 

A variety of photocatalyst supports has been examined experimentally. Dip-coated glass slides or plates have been used in many experimental systems as a simple lab-scale supported photocatalyst system. Coated glass offers many of tlte important features of a supported photocatalyst while still offering relatively simple preparation. Honeycomb monoliths, widely used as commercial catalyst supports for a variety of gas-phase applications, have also been examined as photocatalyst supports (Fig. 3). Although these monoliths offer good stability and excellent throughput, providing illumination for the photocatalyst inside the monolith channels can be problematic [41,42]. Randomly structured support materials, like fiber-based filters, reticulated foams, and similar materials, have been used... 

Antibacterial textile fibers containing titanium oxide photocatalysts... 

Plasma-driven photocatalysis was performed also for degrading gas-phase toluene (Sun et al., 2007), showing a significant increase in the removal of toluene, while decreasing the number of secondary by-products. It is noteworthy that the decrease in the emission of byproducts could be also due to the loading of the photocatalyst on AC fibers, which could operate through the Adsorb and Shuttle mechanism (Paz, in press). 

In typical fixed photocatalytic reactors, the photocatalyst can be coated or anchored on the reactor walls around the light source casing or attached to a solid matrix. Since Ti02 is not present in the water or air streams at any time, these reactors have the intrinsic advantage of not requiring a catalyst recovery operation. Relevant examples of this type of reactor are the coated fiber optic cable reactor and the multiple tube reactor (Peill and Hoffmann, 1995, 1996, 1997, 1998, Ray and Beenackers, 1998a). 

Other options for the fixed photocatalyst design are to entrap the Ti02 particles on glass beads, to immobilize them on fiberglass or woven fibers and to hold particles in ceramic membranes by compression. 

Ti02 coated on an optical fiber bundle. Optical fibers could provide direct photocatalyst radiation transfer and high activated surface area to reactor volume. Care has to be taken, however, because of the possibility of catalyst deactivation due to heat build up in the fiber optic bundle ainay (Peill and Hoffmann, 1996, 1995)... 

Titania powders are extensively used in pigments, as catalyst supports, and more recently in synthesis of inorganic membranes and as photocatalyst in gas and water purification. Silica particles have found applications as optical fibers, fillers. 

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