Electrochemical removal of synthetic methyl orange dyeing wastewater by reverse electrodialysis reactor: Experiment and mineralizing model

In this paper, the synthetic methyl orange (MO) dyeing wastewater treated by a reverse electrodialysis reactor (REDR) with 40 member pairs was investigated first. The boron-doped diamond (BDD) and carbon felt were adopted as an anode and a cathode in the REDR. The influences of operation parameters on the chemical oxygen demand (COD) removal efficiency were detected and explored. Then, a mathematical model of organic miner-alizing was developed for the REDR to predict the variation of COD removal efficiency with treating time under the different operation conditions. Finally, the energy consumption of the wastewater treated by the REDR was analyzed. The results showed that raising the working fluid flowing velocity and electrode rinse solution flowrate improved the COD removal efficiency and instantaneous current efficiency (ICE), and reduced the total energy consumption (TEC) of the REDR. Raising the initial MO concentration could significantly reduce the TEC despite the COD removal efficiency being near. Since the main energy consumed by the REDR was salinity gradient energy (SGE) from waste heat conversion or the natural environment, the energy cost of REDR treating waste-water has been reduced significantly.

Automated summary

This study investigated the application of a reverse electrodialysis reactor (REDR) in treating synthetic methyl orange (MO) dyeing wastewater. The effects of operation parameters on the chemical oxygen demand (COD) removal efficiency were explored and a mathematical model was developed to predict the variation of COD removal efficiency with treating time under different conditions. The results showed that increasing the fluid velocity and rinse solution flowrate improved the COD removal efficiency and reduced the total energy consumption of the REDR.