Thin film photocatalytic reactor for the destruction of organic contaminants in industrial wastewater and drinking water

A novel UV/TiO(2) rotating disk photocatalytic reactor (RDPR) has been developed for the photocatalytic degradation of toxic and hazardous organic compounds in industrial wastewater as well as in groundwater (drinking water application). The rotating disk photocatalytic reactor exhibits certain advantages, such as the formation of a thin film for the reaction, good mixing, use of air as oxygen source and effective immobilization of the TiO(2) catalyst. Other advantages include the flexibility of either catalyst reactivation or replacement during potential deactivation or poisoning. The rotating disk was covered on both sides with attached TiO(2) catalytic pellets and was rotated vertically in the reactor vessel. With half the disk exposed to air, the reaction occurred within a thin film of solution carried on the rotating disk. The effects of disk angular velocity (2 to 20 rpm), pH (3, 7, and 10), and initial contaminant concentration (32 to 320 mu mol/l) on the degradation of 4-chlorobenzoic acid have been investigated. Degradation rates increased with disk angular velocity following a saturation-type dependancy. Higher degradation rates were observed at pH = 3.0 while the effect of initial contaminant concentration on the initial reaction rates followed the Langmuir-Hinshelwood model.