Enhanced sequestration of commercial Auramine O dye in a Fenton oxidative decolourization process

Abstract

The present work investigates the Fenton degradation of commercial Auramine O dye from a model solution through advanced oxidation process (AOP). The effects of initial pH, ferrous ion and H₂O₂ concentration have been evaluated with respect to the extent of decolourization of the feed solution. A maximum decolourization to the tune of 91.8% is accomplished at a pH of 3.0. The effect of various doses of Fe²⁺ and H₂O₂ on the percentage reduction in chemical oxygen demand (COD) is investigated at a constant pH. 84.9% reduction of COD is obtained using a combination of 48 mL/L H₂O₂ and 6 g/L Fe²⁺. The gas chromatography-mass spectrometry analysis reveals the presence of toxic non-biodegradable Auramine O dye in the model solution before the Fenton AOP, which is degraded into several compounds including CO₂ after 30 min of Fenton AOP. The spectral output from FTIR analysis corroborates the molecular rearrangement during Fenton process with consequent degradation.