An immobilized layer-by-layer TiO2/Chitosan (CS) biopolymer onto glass plate has been fabricated, optimized and applied for the removal of 10 mg L−1 phenol and its intermediates under a 45-W fluorescent lamp with a UV leakage irradiance of 4.4 Wm−2. A simple dip-coating technique using the dip-coating solution containing TiO2, epoxidized natural rubber (ENR50) and phenol–formaldehyde resin (PF) was used to immobilize TiO2 onto the CS sub-layer. However, the CS sub-layer did not improve the adsorption of phenol while photodegradation of ENR50 and PF binders acted as macro-pores forming agent within the surface of the TiO2 layer. The degradation kinetics of phenol fitted the pseudo-first order rate model and the main intermediates were qualitatively and quantitatively identified by HPLC analysis to be maleic acid, fumaric acid, hydroquinone and catechol. These intermediates and end-products of the degraded phenol by both TiO2 single layer and layer-by-layer TiO2/CS systems were identical. The total removal of phenol and its intermediates can be achieved within 120 min of irradiation by using layer-by-layer TiO2/CS system, while the same results can be obtained within 360 min of irradiation by using TiO2 single layer.
1. Mills, A, Hunte, SL1997J Photochem Photobiol A108:1.