Immobilization of S-TiO2 on reusable aluminum plates by polysiloxane for photocatalytic degradation of 2,4-dichlorophenol in water

In this work, a highly visible light active and reusable photocatalyst was synthesized by incorporation of sulfur cations into the lattice of titanium dioxide (TiO2). The prepared photocatalyst was immobilized on aluminum plates by polysiloxane for repetitive use in photocatalysis experiments. Suspended and attached catalysts were used for degradation of 2,4-dichlorophenol (2,4-DCP) under direct irradiation of a metal halide lamp. In contrast, the degradation of 2,4-DCP by suspended catalyst was faster than attached catalyst. However, the trends of degradation rates by attached catalyst indicate that the mineralization of 2,4-DCP could be extended for additional time to attain the same efficiency of suspended catalyst. At initial concentration of 25 mg. L-1 the degradation efficiency of 2,4-DCP was higher than 97% after 480 min. The degradation rates in five consecutive cycles were 98%, 96%, 90%, 86%, and 80.4% indicating high reusability and stability of the catalyst even after long periods of photocatalytic reaction. The photocatalytic degradation rates of 2,4-DCP by suspended and attached catalysts were described by Langmuir-Hinshelwood kinetic model.