Electrocoagulation process for the decolorization of wastewater containing Reactive Red 195 and CFD simulation of the hydrodynamic in a continuous-flow single-channel reactor

Abstract

The highly colored textile effluents require efficient treatment before being released into the environment. In this study, a continuous-flow single-channel reactor operating in closed- circuit was used to apply electrocoagulation for the treatment of synthetic textile wastewater. First, the characterization of the hydrodynamic within the reactor is evaluated by Computational Fluid Dynamics simulation using the k-ε turbulence model (Comsol Multiphysics®). Apart from a non-uniform distribution of the velocities inside the reactor, no particular anomaly was observed. Second, the decolorization efficiency was examined under various current intensities, electrolysis times, and initial dye concentrations. By operating under a current intensity of 100 mA instead of 50 mA, the required electrolysis time to achieve a decolorization efficiency of 80% decreased by 40%, while the specific electrode consumption remained slightly unchanged at about 0.19 kg Al·kg−1. At a current intensity of 100 mA and an electrolysis time of 26 min, and the increase in the initial dye concentration from 10 to 50 mg·L−1 the decolorization efficiency decreased remarkably while the specific electrode consumption was kept constant at about 0.15 kg Al·kg−1 dye removed. The knowledge obtained through this study can be used for the transposition from batch to continuous mode. HIGHLIGHTS The EC process was carried out in a recirculation mode.; Comsol Multiphysics was used to perform CFD simulation in order to investigate the transport phenomenon in the CFSC reactor.; The RTD study is used to validate the numerical results obtained by CFD simulation.; The current intensities applied are far lower than in a conventional EC cell.; 0.15 kg/kg was considered to be the limit value of the specific electrode consumption.;

Keywords

• cfd simulation
• cfsc reactor
• decolorization
• electrocoagulation
• rr195
• textile wastewater