Immobilized bilayer TiO2/chitosan system for the removal of phenol under irradiation by a 45 watt compact fluorescent lamp

A simple bilayer system consisting of TiO2 and chitosan (CS) biopolymer has been fabricated and immobilized onto a glass plate. The deposition properties of TiO2 powder were improved by adding epoxidized natural rubber (ENR50) and phenol-formaldehyde resin (PF) in the coating formulation. SEM analysis indicated that the degraded ENR50 acted as macro-pores forming agent to generate macro-pores within the surface of TiO2 layer and was quantitatively determined by TGA and EDX analyses as well. The highly porous structure of immobilized TiO2 layer allows better diffusion of pollutants, increases the light penetration and improves the optical property as indicated by photoluminescence spectroscopy (PLS) analysis. Consequently, the photocatalytic activity and mineralization rate of the immobilized bilayer TiO2/CS system becomes approximately twice as fast as an immobilized TiO2 single layer system and as good as TiO2 powder in a slurry system. Moreover, the adsorption effect was extremely negligible and the photodegradation of phenol was mainly due to the photocatalytic process. (C) 2011 Elsevier B.V. All rights reserved.