| 초록 |
Lignin is one of the most problematic pollutants in paper wastewater because it is a major chemical oxygen demand (COD) component and is responsible for color and turbidity of the paper wastewater. Also it is very hard to degrade for conventional water treatment methods due to many rigid aromatic units on its structure. In my experiments, photocatalytic oxidation method was applied for lignin degradation. To compare photocatalytic mechanism of lignin, TiO2 and ZnO were used.Two photocatalysts showed different lignin degradation rate under UV irradiation (365 nm BLB lamp). Lignin degradation rate with ZnO was retarded at first time but accelerated after 90 minutes. On the other hand, TiO2 showed linear degradation phenomenon with time. These phenomena were explained by the difference of favorable photocatalytic pathway (ZnO: indirect, TiO2: direct). And in presence of Fe(ClO4)3 (additional electron scavenger),degradation efficiency was increased with ZnO but with TiO2, decreased degradation efficiency was observed. These phenomena were explained byH2O2 (natural electron scavenger) consumptionof Fe3+. |
