Chapter 12 - Thin film photocatalytic reactor for the destruction of organic contaminants in industrial wastewater and drinking water

Abstract

This chapter proposes a novel UV/TiO2 rotating disk photocatalytic reactor (RDPR) for the photocatalytic degradation of toxic and hazardous organic compounds in industrial wastewater as well as in groundwater. Photocatalytic reactions occurred in a thin film of liquid on the rotating disk loaded with TiO2 catalytic pellets and illuminated by UV radiation. Photocatalytic investigations in water using 4-chlorobenzoic acid (CBA) as a model organic contaminant show that both the TiO2 catalyst and UV (365 nm) radiation are required for photocatalytic degradation. Although the time required for total organic carbon removal was more than twice that required for 4-CBA degradation, complete mineralization was achieved. The photocatalytic reaction rates increased with the disk angular velocity in the range of 2–20 rpm. The increase in the reaction rates was higher when the disk angular velocity was increased from 2 to 6 rpm. Heterogeneous reactions in the thin liquid film around the vicinity of TiO2 catalyst, immobilization of the catalyst, potential of catalyst replacement after deactivation, and no need of introducing oxygen in the reaction vessel are the advantages of the RDPR.