Design, characterization and performance evaluation of a laboratory-scale continuous reactor for sono-Fenton treatment of simulated wastewater

Abstract

A laboratory scale continuous flow stirred tank reactor (CFSTR) has been developed for ultrasound-assisted Fenton degradation of Rhodamine B dye in simulated wastewater and its performances have been studied in the present work. The sono-reactor was made of glass, 6 cm in diameter and 17.5 cm in height; fitted with a cooling water jacket. The volume was about 0.4 L and the flow rate of dye solution was 20 mL min−1. Ultrasound was provided with a 120 W probe-type sonicator. The hydrodynamic characteristics were studied by RTD studies and CFD analysis in COMSOL Multiphysics software. The CFD analysis showed the reactor to be behaving like a CSTR with bypassing leading to a short residence time. The optimum treatment conditions in this reactor for degrading Rhodamine B solution were determined using Response Surface Methodology. A model equation correlating the decolorization percentage with the initial dye concentration, H2O2 and Fe2+ dosage (Fenton’s reagent) was developed which can predict the decolorization with a high degree of accuracy. Under optimum conditions, the percent decolorization was 55 and the corresponding COD removal was 15 %. A continuous sono-Fenton reactor, if scaled up properly, can be useful for degradation of dark coloured refractory organics in wastewater where photo-Fenton reaction is ineffective.