Photocatalytic degradation of dye effluent by titanium dioxide pillar pellets in aqueous solution

Abstract

Photocatalytic oxidation (PCO) process is an effective way to deal with organic pollutants in wastewater which could be difficult to be degraded by conventional biological treatment methods. Normally the TiO_2 powder in nanometre size range was directly used as photocatalyst for dye degradation in wastewater. However the titanium dioxide powder was arduous to be recovered from the solution after treatment. In this application, a new form of TiO_2 (i.e. pillar pellets ranging from 2.5 to 5.3 mm long and with a diameter of 3.7 mm) was used and investigated for photocatalytic degradation of textile dye effluent. A test system was built with a flat plate reactor (FPR) and UV light source(blacklight and solar simulator as light source respectively) for investigating the effectiveness of the new form of TiO_2. It was found that the photocatalytic process under this configuration could efficiently remove colours from textile dyeing effluent. Comparing with the TiO_2 powder, the pellet was very easy to recovered from the treated solution and can be reused in multiple times without the significant change on the photocatalytic property. The results also showed that to achieve the same photocatalytic performance, the FPR area by pellets was about 91% smaller than required by TiO_2 powder. At least TiO_2 pellet could be used as an alternative form of photocatalyst in applications for textile effluent treatment process, also other wastewater treatment processes.