CdS-sensitized TiO2 in phenazopyridine photo-degradation: catalyst efficiency, stability and feasibility assessment

J Hazard Mater. 2010 Jan 15;173(1-3):318-25. doi: 10.1016/j.jhazmat.2009.08.093. Epub 2009 Aug 25.

Abstract

Mineralization of phenazopyridine, 1, in water, under solar-simulator radiation was efficiently achieved using nanoparticle CdS-sensitized rutile TiO(2), TiO(2)/CdS, 2, as photo-catalysts. Despite that, 2 showed two main drawbacks. Firstly, the system was difficult to recover by simple filtration, and demanded centrifugation. Secondly, the sensitizer CdS showed relatively high tendency to leach out hazardous Cd(2+) ions under photo-degradation reaction conditions. In an attempt to solve out such difficulties, 2 was supported onto sand surface. The sand/TiO(2)/CdS system, 3, was easier to recover but showed slightly lower catalytic activity compared to 2. On the other hand, the support failed to prevent leaching of Cd(2+). This indicates limited future applicability of CdS-sensitized TiO(2) photo-catalyst systems, in solar-based water purification strategies, unless leaching out tendency is completely prevented.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cadmium Compounds / chemistry*
  • Catalysis
  • Feasibility Studies
  • Hydrogen-Ion Concentration
  • Kinetics
  • Luminescence
  • Medical Waste / analysis
  • Microscopy, Electron, Scanning
  • Phenazopyridine / chemistry*
  • Photochemistry
  • Spectrophotometry, Ultraviolet
  • Sulfides / chemistry*
  • Titanium / chemistry*
  • X-Ray Diffraction

Substances

  • Cadmium Compounds
  • Medical Waste
  • Sulfides
  • cadmium sulfide
  • titanium dioxide
  • Titanium
  • Phenazopyridine