Photocatalytic degradation of actual actual textile industrial wastewater in aqueous suspensions of polycrystalline TiO_2

摘要

Heterogeneous photocatlaytic oxidation of contaminants present in wastewater produced by a textile industry was carried out. The samples were withdrawn from the plant before and after a traditional biological treatment. The effluents were named A and A' (before the biological treatment), B and B' (after the biological treatment). Polycrystalline TiO_2 (Degussa P25) was used as the catalyst in a batch photoreactor with immersed lamp. An almost complete decolorization was observed after about 0.5/1 hours for both kinds of effluents, but the decrease of the total organic carbon (TOC) concentration occurred more slowly. The influence of some chemical oxidation rate was also investigated. After addition of H_2O_2 or S_2O_8~(2-) TOC decreased more quickly only for B and B'. The runs performed by using O_3 as bubbling gas showed a mineralization rate higher than that observed in the presence of O_2.