Ultrasound-Assisted Synthesis of Nonmetal-Doped Titanium Dioxide Photocatalysts for Simultaneous H<sub>2</sub> Production and Chemical Oxygen Demand Removal from Industrial Wastewater
Natjakorn Jandam, Karn Serivalsatit, Mali Hunsom, Kejvalee Pruksathorn
Abstract
A series of nonmetal-doped titanium dioxide (Nm x /TiO 2 , where x is the weight fraction of nonmetal elements) photocatalysts was prepared via ultrasonic-assisted impregnation for simultaneous hydrogen (H 2 ) production and chemical oxygen demand (COD) removal from industrial wastewater. Three types of Nm elements, carbon (C), silicon (Si), and phosphorus (P), were explored. The P 1 /TiO 2 exhibited a higher photocatalytic activity for H 2 production and COD removal than the C 1 / TiO 2 and Si 1 /TiO 2 photocatalysts. Approximately 6.43 mmol/g photocatalyst of H 2 was produced, and around 26% COD removal was achieved at a P 1 / TiO 2 loading of 4.0 g/L, a light intensity of 5.93 mW/cm 2 , and a radiation time of 4 h. This is because the P 1 /TiO 2 photocatalyst exhibited lower point of zero charge values and a more appropriate band position compared with other Nm x /TiO 2 photocatalysts to produce H + , which can consequently form H 2 , and reactive oxygen species (HO and O 2