Photocatalytic Degradation of a Gaseous Organic Pollutant

• Jimmy C. Yu ^[1] ; Linda Y. L. Chan ^[1]
  1. [1] Chinese University of Hong Kong

     Chinese University of Hong Kong

     RAE de Hong Kong (China)

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 75, Nº 6 (June), 1998, págs. 750-750
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • A simple and effective method to demonstrate the phenomenon of photocatalytic degradation of a gaseous organic pollutant was developed. Titanium dioxide (anatase) was used as the photocatalyst, and sunlight was found to be an effective light source for the activation of TiO2. The organic pollutant degrade in this demonstration was a common indoor air pollutant, dichloromethane. The TiO2 powder was suspended in a 3:7 ethanol/water solution, and then coated on microscopic slides. The slides together with appropriate indicators were place in 250-mL conical flasks. A small amount of the volatile dichloromethane solvent was injected into each flask, and the flasks were sealed with a piece of parafilm. Some of the flasks were exposed to direct sunlight, and some were kept in the dark. The degradation products of dichloromethane were carbon dioxide, water, and hydrogen chloride. Formation of the acidic HCl gas could be monitored easily by two indicators, the universal pH paper and ammonia. The universal pH paper would change color from green to red in the presence of HCl and H2O, while HCl would react with ammonia to form a white fume. The results of this demonstration showed that both TiO2 and light were required in this photocatalytic degradation process.