Fe(III)/H2O2-Like System for Removal of Azo Dye from Aqueous Solution

Abstract

Fe(III)/H2O2 system is an effective method for separating the organic compounds from aqueous solution, whereas it is often investigated under lower pH conditions. In order to improve performance of the system, a Fe(III)/H2O2-like system that was composed of iron-based coagulant and H2O2 was developed, which has the combined effect of flocculation and oxidation. The system when used for decolorization of an organic azo dye solution, Procion Red MX-5B, under wider pH range, indicated higher decolorization efficiency. Parameters affecting the decolorization such as coagulant dosage, H2O2 concentration, initial solution pH, temperature, and initial dye concentration were examined in this study. The results indicated that with appropriate coagulant dosage, H2O2 concentration, and pH, it was more effective for the decolorization, especially in a weak alkaline environment (pH = 7-8); the pseudo-first-order kinetics could express the azo dye concentration as a function of the reaction time. This study further illustrated that the azo dye solution was degraded to a degree with 53.22% TOC removal at an initial total TOC concentration of 14.92 mg/L. Overall, the established system in this study was favorable to the decolorization of soluble azo dye.