Solar Detoxification of Water: Outdoor Testing of Prototype Photoreactors

One element hampering the creation of commercial photocatalytic detoxification systems is the high cost of ultraviolet (UV) light generated from electric lamps. Analyses have suggested that solar systems can supply UV photons for less cost than electric sources can. The National Renewable Energy Laboratory, through in-house research and subcontracts with industry and university research Facilities, has produced a number of different photoreactor designs for solar detoxification applications. Testing of these designs has shown that low and nonconcentrating units are more efficient than trough concentrator-based systems for detoxification applications. A novel compound-parabolic-concentrator design with favorable attributes of both trough concentrators and one-sun photoreactors is shown to perform nearly as well as a simple one-sun unit. In addition to the solar collector design, researchers investigated the use of fixed catalysts. Two such supported catalyst configurations are reported here along with the baseline slurry case. Results indicate that slurries continue to yield faster rates than supported catalysts.