Optimization of photocatalytic oxidation of 2,2',3,3'-tetrachlorobiphenyl.
Polychlorinated biphenyls (PCBs) are wide spread environmental pollutants. This research focused the optimum physico-chemical conditions under which photocatalytic oxidation (PCO) can be used to degrade 2,2',3,3'-tetrachlorobiphenyl (tetra-CB). Among the optimal physico-chemical conditions studied were UV intensity, hydrogen peroxide (H2O2) and titanium dioxide (TiO2) concentrations, initial pH, and possible reaction intermediates were also determined. The results indicate that the optimal physico-chemical conditions necessary for the degradation of tetra-CB by PCO were UV intensity at 3.16 mW/cm2, 30 mM of H2O2 and 100 mg/l of TiO2. In contrast to the results of PCO studies on other organic compounds, the optimum pH for PCO degradation of tetra-CB was 5.5. The removal efficiency was also higher under acidic conditions than alkaline conditions. Although degradation intermediates such as 1,3-bis(1,1-dimethylethyl)benzene, 2,4-bis(1,1-dimethylethyl)phenol, and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were identified at an early stage in the reaction process, they were not completely degraded even after 7h of PCO reaction.
Wong
K H
KH
Department of Biology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
Tao
S
S
Dawson
R
R
Wong
P K
PK
D002384:Catalysis; D004787:Environmental Pollution / Q000517:prevention & control*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010777:Photochemistry / Q000379:methods*; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000737:chemistry*; D012996:Solutions; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays
D012996:Solutions; C009495:titanium dioxide; C068319:2,2',3,3'-tetrachlorobiphenyl; D006861:Hydrogen Peroxide; D014025:Titanium; D011078:Polychlorinated Biphenyls