Degradation and sludge production of textile dyes by Fenton and photo-Fenton processes

The degradation and decolorization of direct dye (Everdirect supra turquoise blue FBL), acidic dye (Isolan orange S-RL) and vat dye (Indanthrene red FBB) have been investigated by Fenton and UV/Fenton processes. The effects of solution pH, Fe2+ dosages and H2O2 dosages have been studied by jar-test experiments. A comparative study for Fenton and UV/Fenton reactions by photoreactor has also been carried out by scale-up the optimum conditions, obtained through jar-test experiments. Fenton process is highly efficient for color removal for three dyes tested and for TOC removal of FBB and FBL. UV/Fenton showed slighter increase in treatment efficiency than that of Fenton process for both FBB and FBL dye solutions. S-RL improved much more TOC removal% by UV-irradiation. Sludge productions were compared for FeCl3-, FeSO4-coagulation and Fenton reaction in order to prove the dual role of FeSO4 in Fenton process.