Photocatalytic remediation of gamma-HCH contaminated soil induced by alpha-Fe2O3 and TiO2

J Environ Sci (China). 2004;16(6):938-41.

Abstract

Heterogeneous photocatalytic degradation of gamma-HCH on soil surfaces was carried out to evaluate the photocatalytic effectiveness of alpha-Fe2O3 and TiO2 toward degrading gamma-HCH on soil surfaces. After being spiked with gamma-HCH, soil samples were loaded with alpha-Fe2O3 or TiO2 and exposed to UV-light irradiation. Different catalyst loads, 0%, 2%, 5%, 7%, and 10% (wt.) alpha-Fe2O3; 0%, 0.5%, 1%, 2: (wt.)TiO2, were tested for up to 7 d irradiation. The effects of soil thickness, acidity, and humic substances were also investigated. The obtained results indicated that the gamma-HCH photodegradation follows the pseudo-first-order kinetics. The addition of alpha-Fe2O3 or TiO2 accelerates the photodegradation of gamma-HCH, while the photodegradation rate decreases when the content of alpha-Fe2O3 exceeds 7% (wt.). The degradation rate increases with the soil pH value. Humic substances inhibit the photocatalytic degradation of gamma-HCH. Pentachlorocyclohexene, tetrachlorocyclohexene, and trichlorobenzene are detected as photodegradation intermediates, which are gradually degraded with the photodegradation evolution.

MeSH terms

  • Catalysis
  • Coloring Agents / chemistry
  • Ferric Compounds / chemistry
  • Hexachlorocyclohexane / chemistry*
  • Hydrogen-Ion Concentration
  • Photochemistry
  • Soil Pollutants / analysis*
  • Titanium / chemistry

Substances

  • Coloring Agents
  • Ferric Compounds
  • Soil Pollutants
  • titanium dioxide
  • ferric oxide
  • Hexachlorocyclohexane
  • Titanium