Novel TiO₂ Nanocatalysts for Wastewater Purification-Tapping Energy from the Sun

Water treatment using TiO₂ semiconductor as a durable heterogeneous photocatalyst has been the focus of environmentalists in recent years. We currently developed an inexpensive and highly efficient approach for synthesizing nitrogen doped TiO₂ with lower band-gap energy that can respond to visible light. Doping on the molecular scale led to an enhanced nitrogen concentration of up to 21.8%. Reflectance measurements showed the synthesized N-doped TiO₂ nanoparticles are catalytically active with the absorbance that extends into the visible region up to 600nm. The water purification potential of this new class of compounds was evaluated by studying the photodegradation of Acid Orange 7 (AO7) and E. coli. Experiments were conducted to compare the photocatalytic activities of N-doped TiO₂ nanocatalysts and commercially available Degussa P25 power under identical solar light exposure. N-doped TiO₂ demonstrated superior photocatalytic activities in both chemical compound degradation and bactericidal reactions. The result of this study shows the potential of applying new generations of catalyst for wastewater purification and disinfection.