Wool-Fe (III) complex (Wool-Fe) was prepared by a reaction between a wool fiber and ferric chloride at room temperature and characterized using SEM and FT-IR, and then used as a heterogeneous catalyst for the degradation of azo dyes in water. Some factors affecting the degradation of azo dyes such as catalyst dosage, catalyst loading (CFe-wool), irradiation intensity, solution pH and dye structure was investigated with respect to the decoloration percentage and rate constant. Additionally, the photocatalytic degradation of azo dyes was examined by UV-Vis spectrum. The results indicated that wool fibers were able to coordinate with ferric ions in solution, and elevation of temperature and increasing ferric ion concentration led to the high CFe-wool catalysts. Moreover, increasing catalyst dosage and CFe-wool significantly accelerated the dye degradation. Wool-Fe catalyst showed high photocatalytic activity at pH≤6.0 solution, however, its activity was reduced at alkaline medium. Photocatalytic degradation of azo dyes in the presence of Wool-Fe catalyst followed the pseudo-first order kinetic model, and increasing catalyst dosage and CFe-PAN also enhanced the degradation rate constants. Reactive dyes were decomposed more easily than acid dyes in the presence of Wool-Fe catalyst and H2O2 at the same conditions.
