Decoloration of Acid Red 88 Using Synthetic-Zeolite-Based Iron as a Heterogeneous Photo-Fenton Catalyst

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.