Yet, research has focused on the benefits of using activated carbon (AC) as a

catalyst support versus other supports. Uchida et al. (1993) and Lu et al. (1999) found

that while the oxidation rates of a specific compound were lower with the TiO2 loaded

AC, the complete mineralization rates were greater than with a plain slurry of TiO2 or

any other catalyst loaded support. They concluded that the lower oxidation rate can be

attributed to the carbon blocking some of the photons of light from reaching the catalyst

surface and the higher mineralization rate can be attributed to the high adsorptive ability

of the carbon to adsorb the intermediate compounds that are being formed.

 An additional benefit of TiO2 coated carbon is its potential for in situ AC

regeneration. Many water utilities use granular activated carbon (GAC) for the removal

of organic compounds. However, after the absorbent is spent, removal of the carbon from

the system is required for reactivation, disposal in a hazardous waste landfill, or

incineration. While on-site thermal reactivation is an option for some utilities, it is not the

most economical option for many. Therefore, research has been looking at optimizing

both TiO2-coated carbon's adsorption capability and its regeneration efficiency for the

removal and subsequent oxidation of organic pollutants adsorbed on the spent carbon

surface (Crittenden et al., 1993; Khan et al., 2002; Sheintuch and Matatov-Meytal, 1999).

 While activated carbon has some benefits as a catalyst support, its use requires a

reactor that efficiently exposes the catalyst surface to the photons of light. Since this may

require mixing or fluidizing the particles, the inherent attrition can cause the catalyst to

detach itself from the carbon (Lu et al., 1999). An additional problem is that the surface

chemistry of a carbon may hinder effective coating (Khan et al, 2002). The various

methods of activating carbon can create different functional groups on the surface, thus