Photocatalytic remediation of gamma-HCH contaminated soil induced by alpha-Fe2O3 and TiO2.
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.
Zhao
Xu
X
Department of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Quan
Xie
X
Zhao
Ya-Zhi
YZ
Zhao
Hui-Min
HM
Chen
Shuo
S
Chen
Jing-Wen
JW
D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D001556:Hexachlorocyclohexane / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010777:Photochemistry; D012989:Soil Pollutants / Q000032:analysis*; D014025:Titanium / Q000737:chemistry
D004396:Coloring Agents; D005290:Ferric Compounds; D012989:Soil Pollutants; C009495:titanium dioxide; C000499:ferric oxide; D001556:Hexachlorocyclohexane; D014025:Titanium