Abstract

Decoloration and mineralization of an azo dye, Acid Red 88, were conducted using synthetic-zeolite-based Fe as a heterogeneous photo-Fenton catalyst in the presence of ultraviolet (UV) rays and H₂O₂. Under the optimal conditions (pH = 5.5, 17.6 mM H₂O₂, and 4 W m^-2 UVC), 100% decoloration and 90% total organic carbon removal of 0.12 mM Acid Red 88 were achieved in 120 min. The effects of initial pH with time, as well as oxidation, were studied in a batch reactor. It was found that high decoloration was achieved using a heterogeneous Fenton method at pH 7 and lower. The catalyst also had the advantages of low leaching of Fe³⁺ ions and maintenance of a high decoloration in consecutive catalytic treatments. Zeolite-based Fe was successfully used repeatedly (up to three consecutive cycles) for decoloration. A high rate of decoloration was also achieved in the case of continuous operation, although <=0.4 mg L^-1 of Fe were leached into the treated water.

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