Photocatalytic Degradation Of Tannery Wastewater By Using Nanometer-sized TiO₂

Photocatalytic degradation of simulative tannery wastewater had been studied by using nanometer-sized TiO₂ powder as photocatalyst. The better result proved that the means of photocatalytic was feasible to degrade tannery wastewater. On the basis of that experiment above, the tannery wastewater was degraded in the photoreactor by using the nanometer-sized TiO₂/glass thin films prepared by sol-gel processing and the TiO₂/quartz sand thin films prepared by liquid phase deposition processing as photocatalysts. The results showed that when initial pH was 6.7 and the volume of H₂O₂ was 0.3%(v/v), by using the TiO₂/glass films as photocatalyst, the removal rate of CODc_r reached 85.79% after 40mins of irradiation. Besides, when initial pH was 6.7 and the volume of H₂O₂ was 0.5%(v/v), by using the TiO₂/quartz sand films as photocatalyst, the removal rate of CODc_r reached 71.91% after 30mins of irradiation. Later, because of the disadvantadges that TiO₂ has wide band gap and electron and holes are easy to compound, ion-doped TiO₂ films were prepared and experiment result showed that when we took high-pressured ultraviolet lamp and natural light as photo source, the photocatalysis activation of TiO₂ membrane strengthened along with the diminishment of the atom radius. Moreover, the Hg/TiO₂ has the best degradational efficiency that the removal rate of CODc_r reached 50.23% after 15mins of irradiation.