Degradation of azo dye by the fluidised‐bed Fenton process

Abstract

A fluidised‐bed Fenton process was utilised for the homogeneous and heterogeneous Fenton degradation of three azo dyes: CI Reactive Black 5, CI Reactive Orange 16 and CI Reactive Blue 2. The effects of the concentration of Fe2+ and hydrogen peroxide on the decolorisation and degradation of the azo dyes were examined. More than 96% of colour removal of the azo dyes was achieved using the fluidised‐bed Fenton process. Chemical oxygen demand (COD) removal of the three azo dyes followed pseudo‐second‐order kinetics at various Fe2+ and hydrogen peroxide concentrations. COD removal of the three azo dyes increased with increasing Fe2+ concentration and was more than 85%. In addition, the COD removal efficiency of the three types of azo dyes first increased and then decreased as the hydrogen peroxide concentration increased. Presumably, the scavenging effect of hydrogen peroxide on hydroxyl radicals occurs at high concentrations of hydrogen peroxide. The most efficient COD removal was found at 160–220 mg/l hydrogen peroxide. More than 80% of the COD was eliminated at pH 3 in 20 mg/l Fe2+ and 160 mg/l hydrogen peroxide for CI Reactive Black 5, 25 mg/l Fe2+ and 160 mg/l hydrogen peroxide for CI Reactive Orange 16 and 20 mg/l Fe2+ and 160 mg/l hydrogen peroxide for CI Reactive Blue 2.

Fenton oxidation treatment of recalcitrant dye in fluidized bed reactor: Role of SiO2 as carrier and its interaction with fenton's reagent

“…This result is similar to that reported by Pukdee‐Asa et al . using FBF but higher than reported by Su et al . .…”

Highly efficient persulfate oxidation process activated with Fe0 aggregate for decolorization of reactive azo dye Remazol Golden Yellow

“…Thus, dye effluent treated by conventional biological treatment process may no longer meet stringent effluent discharge criteria. A broad range of physico-chemical decolorization methods are currently available, such as adsorption (Somasekhara Reddy and Nirmala, 2014;Pei et al, 2015;Ozbay and Yargic, 2015), membrane separation (Xing et al, 2012), sonophotocatalytic technique (Hemapriyamvadha and Sivasankar, 2015;Rasalingam et al, 2015), and electrochemical methods (Kobya et al, 2003;Raschitor et al, 2014); however, chemical sludge generation, adsorbent regeneration, and maintenance of fouled membranes may raise serious concerns (Pukdee-Asa et al, 2011;Weng et al, 2013).…”

Enhancement of the advanced Fenton process by ultrasound for decolorisation of real textile wastewater

“…A scavenging effect of H 2 O 2 on hydroxyl radicals, associated with a high H 2 O 2 concentration, has also been found in studies of dye degradation . Therefore, an optimum H 2 O 2 dose of 1.03 × 10 −2 m was selected for subsequent sono‐AFP experiments.…”

“…In the chain reaction of Fenton's process, because Fe 3+ ions change slowly back to Fe 2+ ions, the oxidation power decreases with a decreasing amount of Fe 2+ ions . Such insufficiency of the Fe 3+ /Fe 2+ ratio can be avoided by adding ferric salts or iron powder as a source of catalytic iron to Fenton's process, the so‐called Fenton‐like process (Fe 3+ /H 2 O 2 ).…”