Studies on Removal of ions and preparation of NaOCl from the industrial RO reject water by electrodialysis

Abstract

Effective removal of Ca 2+ and Clions from the industrial R.O reject water was achieved using electrodialysis. Under optimized conditions ∼16800 and 30500 ppm of Ca 2+ and Clions could be removed with 60-94% current efficiency and 99% removal efficiency. Other ions including Na + , SO 4 2-, K + and Mg 2+ present in smaller amounts could also be removed. Effective conversion of anodically generated chlorine to sodium hypochlorite (0.2-1.2%) was achieved which is the ideal concentration for its use as an antiviral (COVID-19 mitigation purpose). The conditions including current density and amount of charge passed were varied to identify the optimized condition for maximum efficiency.