A systematic study of the photocatalytic degradation of model pollutants by employing supported and doped TiO2 and ZnO

Abstract

Endocrine disrupting chemicals (EDCs) have emerged as environmental issues, and therefore, they have attracted the attention of the scientific community. Advanced oxidation process (AOP) has the potential to treat various organic pollutants including pesticides and known endocrine disrupting chemicals in wastewater. the study of modifying TiO2 and ZnO in order to reduce the electron-hole recombination and sensitization towards visible light is one of the current favourities in photocatalyst research. Hence, the present study focusses on the preparation, characterization and photocatalytic performance of La3+, Bi3+ and IO3 --doped and zeolite supported TiO2 and ZnO photocatalysts. In order to evaluate the photocatalytic activity of La-doped TiO2 photocatalysts the degradation of the chosen EDCs, viz., MCP and TCP was investigated. The results indicate that the photocatalytic activity of TiO2 towards degradation of MCP and TCP can be greatly improved by loading La on the surface of TiO2. It was also observed that the loaded samples are more active than the corresponding TiO2 and the optimum loading was found to be 1 wt% of La. The highly active IO3 --doped TiO2 was prepared using solid state dispersion method. The prepared IO3 --doped TiO2 catalysts were characterised by XRD, SEM-EDX and UV-Vis spectra. XRD results revealed the formation of brookite phase in addition to the anatase and rutile phases appeared to be beneficial for enhancing the photocatalytic activity. The photocatalytic activity of IO3 --doped TiO2 was evaluated by the photocatalytic oxidation of MCP and TCP. It was observed that the rate of degradation of MCP increases with an increase in IO3 - loading up to an optimum level (1 wt%) and then decreases. The photocatalytic activity of IO3 --doped TiO2 was in the order: 1.0 gt 0.7 gt 1.5 gt 2.0 gt 0.3 gt TiO2. The high activity for 1 wt% IO3 doped TiO2 is probably due to the presence of brookite phase in addition to anatase and rutile phases. newline newline newline